CHAP-Adult: A Reliable and Valid Algorithm to Classify Sitting and Measure Sitting Patterns Using Data From Hip-Worn Accelerometers in Adults Aged 35

Background

Hip-worn accelerometers are commonly used, but data processed using the 100 counts per minute cut point do not accurately measure sitting patterns. We developed and validated a model to accurately classify sitting and sitting patterns using hip-worn accelerometer data from a wide age range of older adults.

Methods

Deep learning models were trained with 30-Hz triaxial hip-worn accelerometer data as inputs and activPAL sitting/nonsitting events as ground truth. Data from 981 adults aged 35-99 years from cohorts in two continents were used to train the model, which we call CHAP-Adult (Convolutional Neural Network Hip Accelerometer Posture-Adult). Validation was conducted among 419 randomly selected adults not included in model training.

Results

Mean errors (activPAL - CHAP-Adult) and 95% limits of agreement were: sedentary time -10.5 (-63.0, 42.0) min/day, breaks in sedentary time 1.9 (-9.2, 12.9) breaks/day, mean bout duration -0.6 (-4.0, 2.7) min, usual bout duration -1.4 (-8.3, 5.4) min, alpha .00 (-.04, .04), and time in ≥30-min bouts -15.1 (-84.3, 54.1) min/day. Respective mean (and absolute) percent errors were: -2.0% (4.0%), -4.7% (12.2%), 4.1% (11.6%), -4.4% (9.6%), 0.0% (1.4%), and 5.4% (9.6%). Pearson's correlations were: .96, .92, .86, .92, .78, and .96. Error was generally consistent across age, gender, and body mass index groups with the largest deviations observed for those with body mass index ≥30 kg/m2.

Conclusions

Overall, these strong validation results indicate CHAP-Adult represents a significant advancement in the ambulatory measurement of sitting and sitting patterns using hip-worn accelerometers. Pending external validation, it could be widely applied to data from around the world to extend understanding of the epidemiology and health consequences of sitting.

Sitting less and moving more for improved metabolic and brain health in type 2 diabetes: 'OPTIMISE your health' trial protocol

Background

Clinical practice guidelines recommend that adults with type 2 diabetes (T2D) sit less and move more throughout the day. The 18-month OPTIMISE Your Health Clinical Trial was developed to support desk-based workers with T2D achieve these recommendations. The two-arm protocol consists of an intervention and control arms. The intervention arm receives 6 months health coaching, a sit-stand desktop workstation and an activity tracker, followed by 6 months of text message support, then 6 months maintenance. The control arm receives a delayed modified intervention after 12 months of usual care. This paper describes the methods of a randomised controlled trial (RCT) evaluating the effectiveness and cost-effectiveness of the intervention, compared to a delayed intervention control.

Methods

This is a two-arm RCT being conducted in Melbourne, Australia. Desk-based workers (≥0.8 full-time equivalent) aged 35–65 years, ambulatory, and with T2D and managed glycaemic control (6.5–10.0% HbA1c), are randomised to the multicomponent intervention (target n = 125) or delayed-intervention control (target n = 125) conditions. All intervention participants receive 6 months of tailored health coaching assisting them to “sit less” and “move more” at work and throughout the day, supported by a sit-stand desktop workstation and an activity tracker (Fitbit). Participants receive text message-based extended care for a further 6-months (6–12 months) followed by 6-months of non-contact (12–18 months: maintenance). Delayed intervention occurs at 12–18 months for the control arm. Assessments are undertaken at baseline, 3, 6, 12, 15 and 18-months. Primary outcomes are activPAL-measured sitting time (h/16 h day), glycosylated haemoglobin (HbA1c; %, mmol/mol) and, cognitive function measures (visual learning and new memory; Paired Associates Learning Total Errors [adjusted]). Secondary, exploratory, and process outcomes will also be collected throughout the trial.

Discussion

The OPTIMISE Your Health trial will provide unique insights into the benefits of an intervention aimed at sitting less and moving more in desk-bound office workers with T2D, with outcomes relevant to glycaemic control, and to cardiometabolic and brain health. Findings will contribute new insights to add to the evidence base on initiating and maintaining behaviour change with clinical populations and inform practice in diabetes management.

Trial registration

ANZCTRN12618001159246.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-13123-x.

Association of Accelerometer-Measured Sedentary Accumulation Patterns With Incident Cardiovascular Disease, Cancer, and All-Cause Mortality

Background Emerging evidence suggests accruing sedentary behavior (SB) in relatively more prolonged periods may convey additional cardiometabolic risks, but few studies have examined prospective outcomes. We examined the association of SB accumulation patterns with incident cardiovascular disease (CVD), cancer, and all-cause mortality (ACM). Methods and Results Data were from 7671 EPIC-Norfolk (European Prospective Investigation Into Cancer and Nutrition-Norfolk) cohort middle- to older-aged adults who wore accelerometers on the right hip for 4 to 7 days. Cox proportional hazards regression modeled associations between 2 measures of SB accumulation and incident CVD, cancer, and ACM. These were usual SB bout duration (the midpoint of each individual's SB accumulation curve, fitted using nonlinear regression) and alpha (hybrid measure of bout frequency and duration, with higher values indicating relatively shorter bouts and fewer long bouts). Models were adjusted for potential confounders, then further for 24-hour time-use compositions. During mean follow-up time of 6.4 years, 339 ACM, 1106 CVD, and 516 cancer events occurred. Elevated rates of incident cancer and ACM were seen with more prolonged SB accumulation (lower alpha, higher usual SB bout duration) but not CVD. For usual SB bout duration and alpha, respectively, the confounder-adjusted hazard ratios per SD of the exposure were 1.12 (95% CI, 1.02-1.23) and 0.88 (95% CI, 0.79-0.98) with incident cancer and 1.16 (95% CI, 1.07-1.26) and 0.80 (95% CI, 0.72-0.89) with ACM (all P<0.05). Further adjustment for 24-hour time use weakened associations with ACM for usual bout duration (hazard ratio, 1.06; 95% CI, 0.97-1.16; P=0.209) and partially for alpha (hazard ratio, 0.87; 95% CI, 0.77-0.99; P=0.029). Conclusions Accruing SB in longer bout durations was associated with higher rates of incident cancer and ACM but not with incident CVD, with some evidence of direct SB accumulation effects independent of 24-hour time use. Findings provide some support for considering SB accumulation as an adjunct target of messaging to "sit less and move more."

Using touchscreen mobile devices-when, where and how: a one-week field study

This cross-sectional study explored the objectively measured Touchscreen Mobile Device (TSMD) use in free-living conditions. Data on TSMD use, gross body posture (lying, sitting, standing, stepping), and location of use (workplace, home, other) were collected over seven consecutive days from 54 adults (mean ± SD, 38 ± 10 years). The average duration of TSMD use was 152 ± 91 min/day, with a TSMD engagement of 51 ± 35 times/day. Participants under 30 years spent significantly more time on their TSMD, averaging 230 ± 108 min/day. By location, 54 ± 17% of use occurred at home and 24 ± 15% at work. The most common posture adopted during any TSMD use was sitting (77 ± 5 2 min/day), with participants also spending considerable time lying down in the home environment (39 ± 49 min/day). These findings provide valuable insights into how adults are using TSMDs, including the postures and locations of use. Further research is needed on the health and wellbeing implications of these usage patterns. Practitioner summary: This study explored Touchscreen Mobile Device (TSMD) use in free-living conditions among 54 adults (mean ± standard deviation, 38 ± 10 years). Participants under 30 years spent significantly more time on their devices. More than half of the time spent using TSMD occurred at home while sitting and lying down.Abbreviations: TSMD: touchscreen mobile device; SD: standard deviation; MSD: musculoskeletal disorder; HDR: higher degree by research; SEES: School of Earth and Environmental Sciences; UK: The United Kingdom; USA: United States of America; SAS: statistical analysis system; ANOVA: analysis of variance; SPSS: statistical package for the social sciences; h: hour; min/d: minutes per day; d: day; ICC: intraclass correlation; CI: confidence interval; min: minute; GPS: global positioning systemsHighlightsTouchscreen mobile device use and gross body posture were quantified objectively.The most common postures for touchscreen mobile device use were lying and sitting.Touchscreen mobile devices were used around twice as much at home than at work.Use at home, with a predominance of the lying posture, needs further investigation.

Dietary and physical activity changes and adherence to WCRF/AICR cancer prevention recommendations following a remotely delivered weight loss intervention for female breast cancer survivors: The Living Well after Breast Cancer randomized controlled trial

BACKGROUND

Diet, exercise, and weight management are key in improving outcomes for breast cancer survivors, with international recommendations for cancer survivors relating to these behaviors. However, few behavioral interventions have reported outcomes aligned specifically with these recommendations.

OBJECTIVE

To evaluate a remotely delivered weight loss intervention versus usual care for female breast cancer survivors, on changes in multiple diet and physical activity behaviors.

DESIGN

A randomized controlled trial with assessments at study baseline, 6-, 12- and 18 months (i.e., mid-intervention, post-intervention, and non-contact follow-up).

PARTICIPANTS/SETTING

Participants were recruited between October 2012 and December 2014 through hospitals in Brisbane (Australia) and the state-based cancer registry. Eligible participants (female, 18-75 years, BMI 25-45 kg/m², diagnosed with stage I-III breast cancer in previous two years) were randomly allocated to intervention (n=79) or usual care (n=80).

INTERVENTION

Participants randomized to the intervention group received 22 counseling telephone calls targeting diet and physical activity aimed at achieving 5-10% weight loss, and optional text messages, over 12 months. Usual care participants received their standard medical care and brief feedback following each assessment, which was similar to that provided to intervention participants with the exception that usual care participants' results were not compared to national and study recommendations.

MAIN OUTCOME MEASURES

Dietary intake (24-hour recalls); physical activity (hip-worn Actigraph); sitting time (thigh-worn activPAL3); and, adherence to World Cancer Research Fund/American Cancer Research Institute (WCRF/AICR) recommendations for cancer survivors (0-7 score) were measured at each assessment, with data collected between November 2012 and October 2016.

STATISTICAL ANALYSES PERFORMED

Intervention effects were assessed by linear mixed models, accounting for repeated measures and baseline values. Significance was set at P<0.05.

RESULTS

At baseline, participants were (mean±SD) aged 55±9 years, with a BMI of 31.4±5.0 kg/m², 10.7±5.0 months post-diagnosis, and primarily non-minority. At baseline, only 8% (n=12) of participants met ≥5/7 WCRF/AICR recommendations (mean±SD WCRF/AICR adherence score: 3.8±1.0). At 12 months, significant intervention effects were observed in walking/running ( +21 mins/week; 95%CI: 4, 38) and WCRF/AICR adherence scores (+0.3 points; 95%CI: 0.0, 0.6) only. At 18 months, significant intervention effects were observed for energy intake (-229 kcal/day energy; 95%CI: -373, -84), total fat (-10 g/day; 95%CI: -18, -2), and saturated fat (-5 g/day; 95%CI: -9, -1), and were sustained for WCRF/AICR adherence scores (+0.5 points; 95%CI: 0.2, 0.8).

CONCLUSIONS

This remotely delivered weight loss intervention led to sustained improvements in WCRF/AICR adherence scores, and some improvements in diet and physical activity. These findings provide support for the health benefit of programs targeting lifestyle behaviors in line with cancer survivor recommendations, and the potential for dissemination of such programs following treatment for early-stage female breast cancer.

Alternatives for Measuring Sitting Accumulation in Workplace Surveys

OBJECTIVES

To develop and assess the measurement properties of self-report measures of accumulation of sitting time.

METHODS

Seven candidate measures were collected in 51 workers from three office environments (79% women) via online questionnaire administered immediately before and after 7-day monitoring periods (activPAL3 24-hour protocol with diary recorded work hours).

RESULTS

Three measures had some validity (P < 0.05 vs activPAL): % of sitting in long bouts more than or equal to 30 minutes, sitting strategy frequency (0 to 100), and interruption rate (n/h sitting). Agreement was limited. Some reliability (intraclass correlation or kappa P < 0.05) was seen for these measures, strategy variety (0 to 100), typical day (five categories), and making a conscious effort to sit less (yes/no).

CONCLUSIONS

Two brief and one longer option may suit workplace studies requiring self-report measures of sitting accumulation. Validity was weaker for sitting accumulation than sitting time.

Effect of a Remotely Delivered Weight Loss Intervention in Early-Stage Breast Cancer: Randomized Controlled Trial

Limited evidence exists on the effects of weight loss on chronic disease risk and patient-reported outcomes in breast cancer survivors. Breast cancer survivors (stage I-III; body mass index 25-45 kg/m²) were randomized to a 12-month, remotely delivered (22 telephone calls, mailed material, optional text messages) weight loss (diet and physical activity) intervention (n = 79) or usual care (n = 80). Weight loss (primary outcome), body composition, metabolic syndrome risk score and components, quality of life, fatigue, musculoskeletal pain, menopausal symptoms, fear of recurrence, and body image were assessed at baseline, 6 months, 12 months (primary endpoint), and 18 months. Participants were 55 ± 9 years and 10.7 ± 5.0 months post-diagnosis; retention was 81.8% (12 months) and 80.5% (18 months). At 12-months, intervention participants had significantly greater improvements in weight (-4.5% [95%CI: -6.5, -2.5]; p < 0.001), fat mass (-3.3 kg [-4.8, -1.9]; p < 0.001), metabolic syndrome risk score (-0.19 [-0.32, -0.05]; p = 0.006), waist circumference (-3.2 cm [-5.5, -0.9]; p = 0.007), fasting plasma glucose (-0.23 mmol/L [-0.44, -0.02]; p = 0.032), physical quality of life (2.7 [0.7, 4.6]; p = 0.007; Cohen's effect size (d) = 0.40), musculoskeletal pain (-0.5 [-0.8, -0.2]; p = 0.003; d = 0.49), and body image (-0.2 [-0.4, -0.0]; p = 0.030; d = 0.31) than usual care. At 18 months, effects on weight, adiposity, and metabolic syndrome risk scores were sustained; however, significant reductions in lean mass were observed (-1.1 kg [-1.7, -0.4]; p < 0.001). This intervention led to sustained improvements in adiposity and metabolic syndrome risk.

A RE-AIM evaluation in early adopters to iteratively improve the online BeUpstanding™ program supporting workers to sit less and move more

Background

The web-based BeUpstanding program supports desk workers to sit less and move more. Successfully translated from a research-delivered intervention, BeUpstanding has gone through iterative development and evaluation phases in preparation for wide-scale implementation. In the third planned “early-adopters” phase (01/09/2017–11/06/2019), the program was made freely-available online. An integrated delivery and evaluation platform was also developed to enable workplace champions to run and evaluate the intervention within their work team independent of researcher support. Using the RE-AIM (Reach, Effectiveness, Adoption, Implementation, Maintenance) framework, this study reports on the extent to which the program and processes were “fit-for-purpose” for a national implementation trial across the indicators of uptake (reach and adoption), implementation and engagement, and effectiveness for behaviour change.

Methods

Data were collected via the online surveys embedded in the program and through program access analytics. Descriptive data (with linearized variance for the clustered staff-level data) and results from mixed models (repeated data and clustering for pre-post changes) are reported.

Results

Despite purposeful limited promotion, uptake was good, with 182 Australian users initially registering (208 total) and 135 (from 113 organisations) then completing the sign-up process. Recruitment reached users across Australia and in 16 of 19 Australian industries. Implementation was inconsistent and limited, with signed-up users completing 0 to 14 of the program’s 14 steps and only 7 (5.2%) completing all seven core steps. Many champions (n = 69, 51.1%) had low engagement (1 day toolkit usage) and few (n = 30, 22%) were highly engaged (> 1 day toolkit usage and surveyed staff). Although only 18 users (7 organisations) performed the pre- and post-program staff evaluations (337 and 167 staff, respectively), pre-post changes showed the program effectively reduced workplace sitting by − 9.0% (95% CI -12.0, − 5.9%).

Discussion

The program had uptake across industries and across Australia, but implementation and engagement varied widely. Few workplaces completed the evaluation components. In those that did, the program was effective for the primary outcome (workplace sitting). Conducting a planned early adopters phase and a comprehensive evaluation according to RE-AIM helped highlight necessary program improvements to make it more suitable for wide-scale implementation and evaluation.

Trial registration

Australian and New Zealand Clinic Trials Registry ACTRN12617000682347. Date registered: 12/05/2017.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-11993-1.

Descriptive Epidemiology of Interruptions to Free-Living Sitting Time in Middle-Age and Older Adults

National guidelines recommend physically active interruptions to sitting time, however, the characteristics of these interruptions are broadly stated and ill-defined. A robust methodology for population surveillance for such interruptions is needed.

PURPOSE

To describe the frequency and characteristics (i.e., duration, stepping time, and estimated intensity) of all interruptions and physically active interruptions to adults' free-living sitting time (i.e., transitions from sitting to upright posture) across segments of the population.

METHODS

Australian Diabetes, Obesity and Lifestyle (AusDiab) study participants (321 men; 406 women; mean ± SD 58.0 ± 10.3 years) wore the activPAL3TM for ≥1 valid day. The characteristics of interruptions from laboratory studies demonstrating health benefits were selected to define active interruptions (≥5 min upright and/or ≥ 2 min stepping) and ambulatory interruptions (≥2 min stepping). The frequency and characteristics of all, active, and ambulatory interruptions were described and compared by age, gender, diabetes status, and body mass index.

RESULTS

Adults averaged 55.0 ± 21.8 interruptions per day, but only 20.3 ± 6.7 were active and 14.0 ± 5.4 were ambulatory. Median (25th, 75th percentile) duration was 2.6 (0.9, 7.8) minutes, stepping time was 0.8 (0.3, 2.0) minutes, and estimated energy expenditure was 4.3 (1.4, 12.5) MET-min. Those who were older, had obesity, or had diabetes had significantly (p < 0.05) fewer interruptions of all types and less stepping time during active interruptions than their counterparts (Cohen's d < 0.2).

CONCLUSION

Free-living interruptions were often less active than interruptions performed in effective acute laboratory studies and their content varied widely between population groups. Monitoring all interruptions as well as those that are more active is advisable to provide a comprehensive understanding of free-living sedentary behavior.

Sedentary time in people with obstructive airway diseases

Sedentary time (ST) and light-intensity physical activity (LIPA) are movement behaviours associated with important health outcomes, but are not widely explored in respiratory diseases. We aimed to describe their volume and/or accumulation patterns in moderate-severe COPD, bronchiectasis and severe asthma using the accurate postural-based accelerometer activPAL, contrasting these values with a non-respiratory population. We also sought to test the cross-sectional associations of these behaviours with disease characteristics by diagnostic group, and as a combined label-free disease group.

RESULTS

Adults with COPD (n = 64), bronchiectasis (n = 61), severe asthma (n = 27), and controls (n = 61) underwent cross-sectional measurements of volume and/or accumulation patterns of ST and LIPA. The prevalence and characteristics, and associations with exercise capacity, health-status, airflow-limitation, dyspnoea, systemic inflammation and exacerbations were analysed. ST volumes in COPD were higher than that of bronchiectasis and severe asthma. Values in bronchiectasis and severe asthma were similar to each other and controls (≈8.9 h/day). Their accumulation patterns were also significantly better than in COPD, but similar if not worse compared to controls. LIPA volumes in bronchiectasis and severe asthma were also higher than those of COPD (p < 0.05) and controls. In bronchiectasis and COPD, lower levels/better patterns of ST accumulation, as well as higher LIPA volume were associated with better clinical characteristics. These associations may be mediated by airflow limitation.

CONCLUSIONS

The discordance between engagement in ST volume versus ST patterns highlights the importance of accounting for both these different yet complementary metrics. ST and LIPA are low-intensity activities associated with important clinical characteristics in people with chronic respiratory diseases.

TRIAL REGISTRATION

Not applicable.

Translating research into practice: outcomes from the Healthy Living after Cancer partnership project

BACKGROUND

Healthy Living after Cancer (HLaC) was a national dissemination and implementation study of an evidence-based lifestyle intervention for cancer survivors. The program was imbedded into existing telephone cancer information and support services delivered by Australian state-based Cancer Councils (CC). We report here the reach, effectiveness, adoption, implementation, and maintenance of the program.

METHODS

In this phase IV study (single-group, pre-post design) participants - survivors of any type of cancer, following treatment with curative intent - received up to 12 nurse/allied health professional-led telephone health coaching calls over 6 months. Intervention delivery was grounded in motivational interviewing, with emphasis on evidence-based behaviour change strategies. Using the RE-AIM evaluation framework, primary outcomes were reach, indicators of program adoption, implementation, costs and maintenance. Secondary (effectiveness) outcomes were participant-reported anthropometric, behavioural and psychosocial variables including: weight; physical activity; dietary intake; quality-of-life; treatment side-effects; distress; and fear of cancer recurrence and participant satisfaction. Changes were evaluated using linear mixed models, including terms for timepoint (0/6 months), strata (Cancer Council), and timepoint x strata.

RESULTS

Four of 5 CCs approached participated in the study. In total, 1183 cancer survivors were referred (mostly via calls to the Cancer Council telephone information service). Of these, 90.4% were eligible and 88.7% (n = 791) of those eligible consented to participate. Retention rate was 63.4%. Participants were mostly female (88%), aged 57 years and were overweight (BMI = 28.8 ± 6.5 kg/m2). Improvements in all participant-reported outcomes (standardised effect sizes of 0.1 to 0.6) were observed (p < 0.001). The program delivery costs were on average AU$427 (US$296) per referred cancer survivor.

CONCLUSIONS

This telephone-delivered lifestyle intervention, which was feasibly implemented by Cancer Councils, led to meaningful and statistically significant improvements in cancer survivors' health and quality-of-life at a relatively low cost.

TRIAL REGISTRATION

Australian and New Zealand Clinical Trials Registry (ANZCTR) - ACTRN12615000882527 (registered on 24/08/2015).

Supporting Workers to Sit Less and Move More Through the Web-Based BeUpstanding Program: Protocol for a Single-Arm, Repeated Measures Implementation Study

BACKGROUND

The web-based BeUpstanding Champion Toolkit was developed to support work teams in addressing the emergent work health and safety issue of excessive sitting. It provides a step-by-step guide and associated resources that equip a workplace representative-the champion-to adopt and deliver the 8-week intervention program (BeUpstanding) to their work team. The evidence-informed program is designed to raise awareness of the benefits of sitting less and moving more, build a supportive culture for change, and encourage staff to take action to achieve this change. Work teams collectively choose the strategies they want to implement and promote to stand up, sit less, and move more, with this bespoke and participative approach ensuring the strategies are aligned with the team's needs and existing culture. BeUpstanding has been iteratively developed and optimized through a multiphase process to ensure that it is fit for purpose for wide-scale implementation.

OBJECTIVE

The study aimed to describe the current version of BeUpstanding, and the methods and protocol for a national implementation trial.

METHODS

The trial will be conducted in collaboration with five Australian workplace health and safety policy and practice partners. Desk-based work teams from a variety of industries will be recruited from across Australia via partner-led referral pathways. Recruitment will target sectors (small business, rural or regional, call center, blue collar, and government) that are of priority to the policy and practice partners. A minimum of 50 work teams will be recruited per priority sector with a minimum of 10,000 employees exposed to the program. A single-arm, repeated-measures design will assess the short-term (end of program) and long-term (9 months postprogram) impacts. Data will be collected on the web via surveys and toolkit analytics and by the research team via telephone calls with champions. The Reach, Effectiveness, Adoption, Implementation, and Maintenance Framework will guide the evaluation, with assessment of the adoption/reach of the program (the number and characteristics of work teams and participating staff), program implementation (completion by the champion of core program components), effectiveness (on workplace sitting, standing, and moving), and maintenance (sustainability of changes). There will be an economic evaluation of the costs and outcomes of scaling up to national implementation, including intervention affordability and sustainability.

RESULTS

The study received funding in June 2018 and the original protocol was approved by institutional review board on January 9, 2017, with national implementation trial consent and protocol amendment approved March 12, 2019. The trial started on June 12, 2019, with 48 teams recruited as of December 2019.

CONCLUSIONS

The implementation and multimethod evaluation of BeUpstanding will provide the practice-based evidence needed for informing the potential broader dissemination of the program.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry ACTRN12617000682347; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=372843&isReview=true.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/15756.

Temporal features of sitting, standing and stepping changes in a cluster-randomised controlled trial of a workplace sitting-reduction intervention

Background

There is now a body of evidence on the effectiveness of interventions to reduce workplace sitting time. However, there has been limited reporting of how such interventions may impact behaviour both during and outside of work. Sitting, standing and stepping changes following a workplace intervention were examined across five timeframes (work time on work days; non-work time on work days; work days; non-work days; overall (i.e. work and non-work time on all days)), and the relationships between changes during and outside of work was assessed.

Methods

The cluster-randomised controlled trial, ‘Stand Up Victoria’, delivered a multi-component workplace-delivered intervention that successfully reduced workplace and overall sitting time (relative to controls). Separately, over the five timeframes, changes in device (activPAL3)-assessed outcomes — sitting; prolonged sitting (≥30 min bouts); standing; and, stepping — were compared between intervention (n = 114) and controls (n = 84), along with the time-course of sitting changes during work hours, using mixed models. The potential relationships of changes during work with changes outside of work were examined using compositional data analysis.

Results

On workdays, intervention participants significantly (p < 0.05) improved their activity profile relative to controls, with reduced sitting (− 117 min/8-h workday, 95% CI: − 141, − 93) and prolonged sitting (− 77 min/8 h workday, 95% CI: − 101, − 52); increased standing (114 min/8 h workday, 95% CI: 92, 136) and maintenance of stepping (3 min/8 h workday, 95% CI: − 7, 11, p = 0.576). Effects were nearly identical for time at work; similar but slightly weaker for overall; and, small and non-significant outside of work on workdays and non-work days. Improvements occurred at all times, but not equally, during work hours (p < 0.001). Correlations between changes during and outside of work on workdays were very weak in both the intervention group (r = − 0.07) and controls (r = − 0.09).

Conclusions

Sitting time was reduced almost exclusively during work hours (via replacement with standing), with reductions evident during all working hours, to varying degrees. There was no evidence of compensation, with minimal change in activity outside of work, in response to changes in activity at work. Future interventions may benefit from exploring how best to elicit change throughout the whole day, and across work and non-work domains.

Trial registration

This trial was prospectively registered with the Australian New Zealand Clinical Trials register (ACTRN12611000742976) on 15 July 2011

Cardiometabolic Impact of Changing Sitting, Standing, and Stepping in the Workplace

BACKGROUND

According to cross-sectional and acute experimental evidence, reducing sitting time should improve cardiometabolic health risk biomarkers. Furthermore, the improvements obtained may depend on whether sitting is replaced with standing or ambulatory activities. Based on data from the Stand Up Victoria multicomponent workplace intervention, we examined this issue using compositional data analysis-a method that can examine and compare all activity changes simultaneously.

METHODS

Participants receiving the intervention (n = 136 ≥ 0.6 full-time equivalent desk-based workers, 65% women, mean ± SD age = 44.6 ± 9.1 yr from seven worksites) were asked to improve whole-of-day activity by standing up, sitting less, and moving more. Their changes in the composition of daily waking hours (activPAL-assessed sitting, standing, and stepping) were quantified then tested for associations with concurrent changes in cardiometabolic risk (CMR) scores and 14 biomarkers concerning body composition, glucose, insulin, and lipid metabolism. Analyses were by mixed models, accounting for clustering (3 months, n = 105-120; 12 months, n = 80-97).

RESULTS

Sitting reduction was significantly (P < 0.05) associated only with lower systolic blood pressure at 3 months, and with CMR scores, weight, body fat, waist circumference, diastolic blood pressure, and fasting triglycerides, total/HDL cholesterol, and insulin at 12 months. Significant differences between standing and stepping were only observed for systolic blood pressure and insulin; both favored stepping. However, replacing sitting with standing was significantly associated only with improvements in CMR scores, whereas replacing sitting with stepping was significantly associated with CMR scores and six biomarkers.

CONCLUSIONS

Improvements in several cardiometabolic health risk biomarkers were significantly associated with sitting reductions that occurred in a workplace intervention. The greatest degree and/or widest range of cardiometabolic benefits appeared to occur with long-term changes, and when increasing ambulatory activities.

TRIAL REGISTRATION

ACTRN1211000742976.

Associations of context-specific sitting time with markers of cardiometabolic risk in Australian adults

Background

High volumes of sitting time are associated with an elevated risk of type 2 diabetes and cardiovascular disease, and with adverse cardiometabolic risk profiles. However, previous studies have predominately evaluated only total sitting or television (TV) viewing time, limiting inferences about the specific cardiometabolic health impacts of sitting accumulated in different contexts. We examined associations of sitting time in four contexts with cardiometabolic risk biomarkers in Australian adults.

Methods

Participants (n = 3429; mean ± SD age 58 ± 10 years) were adults without clinically diagnosed diabetes or cardiovascular disease from the 2011–2012 Australian Diabetes, Obesity and Lifestyle (AusDiab) study. Multiple linear regressions examined associations of self-reported context-specific sitting time (occupational, transportation, TV-viewing and leisure-time computer use) with a clustered cardiometabolic risk score (CMR) and with individual cardiometabolic risk biomarkers (waist circumference, BMI, resting blood pressure, triglycerides, HDL- and LDL-cholesterol, and fasting and 2-h post-load plasma glucose).

Results

Higher CMR was significantly associated with greater TV-viewing and computer sitting time (b [95%CI] = 0.07 [0.04, 0.09] and 0.06 [0.03, 0.09]), and tended to be associated with higher occupational and transport sitting time (0.01 [− 0.01, 0.03] and 0.03 [− 0.00, 0.06]), after adjustment for potential confounders. Furthermore, keeping total sitting time constant, accruing sitting via TV-viewing and computer use was associated with significantly higher CMR (0.05 [0.02, 0.08] and 0.04 [0.01, 0.06]), accruing sitting in an occupational context was associated with significantly lower CMR (− 0.03 [− 0.05, − 0.01]), while no significant association was seen for transport sitting (0.00 [− 0.03, 0.04]). Results varied somewhat between the respective biomarkers; however, higher sitting time in each domain tended to be associated detrimentally with individual biomarkers except for fasting glucose (non-significant associations) and systolic blood pressure (a beneficial association was observed). Overall, associations were stronger for TV-viewing and computer use, and weaker for occupational sitting.

Conclusions

Higher context-specific sitting times tended to be detrimentally associated, albeit modestly, with CMR and several cardiometabolic risk biomarkers. There was some evidence suggesting that the context in which people sit is relevant above and beyond total sitting time. Methodological issues notwithstanding, these findings may assist in identifying priorities for sitting-reduction initiatives, in order to achieve optimal cardiometabolic health benefits.

Electronic supplementary material

The online version of this article (10.1186/s12966-018-0748-3) contains supplementary material, which is available to authorized users.

What strategies do desk-based workers choose to reduce sitting time and how well do they work? Findings from a cluster randomised controlled trial

Background

Large amounts of sitting at work have been identified as an emerging occupational health risk, and findings from intervention trials have been reported. However, few such reports have examined participant-selected strategies and their relationships with behaviour change.

Methods

The Stand Up Victoria cluster-randomised controlled trial was a workplace-delivered intervention comprising organisational, environmental and individual level behaviour change strategies aimed at reducing sitting time in desk-based workers. Sit-stand workstations were provided, and participants (n = 134; intervention group only) were guided by health coaches to identify strategies for the ‘Stand Up’, ‘Sit Less’, and ‘Move More’ intervention targets, including how long they would stand using the workstation. Three-month workplace sitting and activity changes (activPAL3-assessed total sitting, prolonged sitting (i.e., sitting ≥30 min continuously) and purposeful walking) were evaluated in relation to the number (regression analysis) and types of strategies (decision-tree analysis).

Results

Over 80 different strategies were nominated by participants. Each additional strategy nominated for the ‘Stand Up’ intervention target (i.e. number of strategies) was associated with a reduction in prolonged sitting of 27.6 min/8-h workday (95% CI: -53.1, − 2.1, p = 0.034). Types of strategies were categorised into 13 distinct categories. Strategies that were task-based and phone-based were common across all three targets. The decision tree models did not select any specific strategy category as predicting changes in prolonged sitting (‘Stand Up’), however four strategy categories were identified as important for total sitting time (‘Sit Less’) and three strategy categories for purposeful walking (‘Moving More’). The uppermost nodes (foremost predictors) were nominating > 3 h/day of workstation standing (reducing total workplace sitting) and choosing a ‘Move More’ task-based strategy (purposeful walking).

Conclusions

Workers chose a wide range of strategies, with both strategy choice and strategy quantity appearing relevant to behavioural improvement. Findings support a tailored and pragmatic approach to encourage a change in sitting and activity in the workplace. Evaluating participant-selected strategies in the context of a successful intervention serves to highlight options that may prove feasible and effective in other desk-based workplace environments.

Trial registration

This trial was prospectively registered with the Australian New Zealand Clinical Trials register (ACTRN12611000742976) on 15 July 2011,

Electronic supplementary material

The online version of this article (10.1186/s12966-018-0731-z) contains supplementary material, which is available to authorized users.

Associations of office workers' objectively assessed occupational sitting, standing and stepping time with musculoskeletal symptoms

We examined the association of musculoskeletal symptoms (MSS) with workplace sitting, standing and stepping time, as well as sitting and standing time accumulation (i.e. usual bout duration of these activities), measured objectively with the activPAL3 monitor. Using baseline data from the Stand Up Victoria trial (216 office workers, 14 workplaces), cross-sectional associations of occupational activities with self-reported MSS (low-back, upper and lower extremity symptoms in the last three months) were examined using probit regression, correcting for clustering and adjusting for confounders. Sitting bout duration was significantly (p < 0.05) associated, non-linearly, with MSS, such that those in the middle tertile displayed the highest prevalence of upper extremity symptoms. Other associations were non-significant but sometimes involved large differences in symptom prevalence (e.g. 38%) by activity. Though causation is unclear, these non-linear associations suggest that sitting and its alternatives (i.e. standing and stepping) interact with MSS and this should be considered when designing safe work systems. Practitioner summary: We studied associations of objectively assessed occupational activities with musculoskeletal symptoms in office workers. Workers who accumulated longer sitting bouts reported fewer upper extremity symptoms. Total activity duration was not significantly associated with musculoskeletal symptoms. We underline the importance of considering total volumes and patterns of activity time in musculoskeletal research.

Correlates of physical activity and sedentary time in young adults: the Western Australian Pregnancy Cohort (Raine) Study

Background

The socioecological model proposes a wide array of factors that influence behaviours. There is a need to understand salient correlates of these activity behaviours in a specific population. However, few studies identified socio-demographic, behavioural, physical, and psychological correlates of objectively-assessed physical activity and sedentary time in young adults.

Methods

This was a cross-sectional analysis of participants in the Raine Study (a pregnancy cohort started in 1989). Australian young adults (mean 22.1 years ± SD 0.6) wore Actigraph GT3X+ accelerometers on the hip 24 h/day for seven days to assess moderate-to-vigorous physical activity (MVPA) and sedentary time (n = 256 women, n = 219 men). Potential correlates were assessed via clinical assessment and questionnaire and included socio-demographic variables (ethnicity, relationship status, work/study status, education, mothers education), health behaviours (food intake, alcohol consumption, smoking status, sleep quality), and physical and psychological health aspects (anthropometrics, diagnosed disorders, mental health, cognitive performance). Backwards elimination (p < 0.2 for retention) with mixed model regressions were used and the gender-stratified analyses were adjusted for demographic variables, waking wear time and number of valid days.

Results

Increased time spent in MVPA was associated with: being single (IRR 1.44 vs in a relationship living together, 95%CI: 1.17, 1.77, p = .001) in women; and better sleep quality in men (lower scores better IRR 0.97, 95%CI: 0.93, 1.00). Less time spent sedentary was associated with: lower mother’s education (− 32.1 min/day, 95%CI -52.9, 11.3, p = 0.002 for having mother with no university degree vs at least a baccalaureate degree) and smoking (− 44.3 min/day, 95%CI: - 72.8, − 15.9, p = .0002) for women; lower education status (− 32.1 min/day, 95%CI: -59.5, − 4.8, p = 0.021 for having no university degree vs at least a baccalaureate degree) and lower depression scores in men (− 2.0, 95%CI: - 3.5, − 0.4, p = 0.014); more alcoholic drinks per week for women (− 1.9 min/day, 95%CI: -3.1, − 0.6, p = 0.003) and men (− 1.0, 95%CI: -1.8, − 0.3, p = 0.007).

Conclusions

Less desirable correlates were associated with positive levels of activity in young Australian adult women and men. Interventions to increase MVPA and decrease sedentary activity in young adults need to specifically consider the life stage of young adults.

Electronic supplementary material

The online version of this article (10.1186/s12889-018-5705-1) contains supplementary material, which is available to authorized users.

Prolonged uninterrupted sitting elevates postprandial hyperglycaemia proportional to degree of insulin resistance

Prolonged uninterrupted sitting is related adversely to cardiometabolic risk markers and postprandial hyperglycaemia, relative to sitting interrupted by regular brief activity breaks. However, whether the magnitude of hyperglycaemic responses to prolonged sitting is dependent upon the underlying degree of insulin resistance remains unclear. Data were pooled from 3 randomized cross-over laboratory-based trials (n = 62) that examined the postprandial blood glucose- and insulin-lowering effects of prolonged sitting vs sitting interrupted by regular brief activity breaks in overweight/obese adults who had normal or impaired glucose metabolism (2 trials) or type 2 diabetes not treated by insulin (1 trial). Corrected for study effects, the magnitude of differences in postprandial glucose and insulin responses between the 2 conditions was significantly exacerbated with poorer baseline levels of fasting glucose, insulin and/or surrogate markers of β-cell function and insulin resistance. This suggests that those with higher underlying levels of insulin resistance may derive greater metabolic benefits from regularly interrupting prolonged sitting than their healthier counterparts. If these findings can be replicated, they may have implications for future targeting and optimization of physical activity/sedentary behaviour interventions in the prevention and management of type 2 diabetes.

Associations of sitting accumulation patterns with cardio-metabolic risk biomarkers in Australian adults

Background

High amounts of time spent sitting can increase cardiovascular disease risk and are deleteriously associated cardio-metabolic risk biomarkers. Though evidence suggests that accruing sitting time in prolonged periods may convey additional risk, verification using high-quality measures is needed. We examined this issue in adults from the Australian Diabetes, Obesity and Lifestyle Study, using accurate measures of sitting accumulation.

Methods

In 2011/12, 739 adults aged 36 to 89 years (mean±SD 58±10 years) wore activPAL3^™ monitors (which provide accurate objective measures of sitting); 678 provided ≥4 valid days of monitor data and complete cardio-metabolic biomarker and confounder data. Multivariable linear regression models examined associations of sitting time, sitting time accrued in ≥30 minute bouts (prolonged sitting time), and three measures of sitting accumulation patterns with cardio-metabolic risk markers: body mass index (BMI), waist circumference, blood pressure, high- and low- density lipoprotein (HDL and LDL) cholesterol, triglycerides, glycated haemoglobin (HbA1c), fasting plasma glucose (FPG) and 2-hour post-load glucose (PLG). Interactions tests examined whether associations of sitting time with biomarkers varied by usual sitting bout duration.

Results

Adjusted for potential confounders, greater amounts of sitting time and prolonged sitting time were significantly (p<0.05) deleteriously associated with BMI, waist circumference, HDL cholesterol, and triglycerides. Total sitting time was also significantly associated with higher PLG. Sitting accumulation patterns of frequently interrupted sitting (compared to patterns with relatively more prolonged sitting) were significantly beneficially associated with BMI, waist circumference, HDL cholesterol, triglycerides, PLG, and with FPG. Effect sizes were typically larger for accumulation patterns than for sitting time. Significant interactions (p<0.05) showed that associations of sitting time with HDL, triglycerides and PLG became more deleterious the longer at a time sitting was usually accumulated.

Conclusions

Adding to previous evidence reliant on low-quality measures, our study showed that accumulating sitting in patterns where sitting was most frequently interrupted had significant beneficial associations with several cardio-metabolic biomarkers and that sitting for prolonged periods at a time may exacerbate some of the effects of sitting time. The findings support sedentary behavior guidelines that promote reducing and regularly interrupting sitting.

Intervening to reduce workplace sitting: mediating role of social-cognitive constructs during a cluster randomised controlled trial

Background

The Stand Up Victoria multi-component intervention successfully reduced workplace sitting time in both the short (three months) and long (12 months) term. To further understand how this intervention worked, we aimed to assess the impact of the intervention on four social-cognitive constructs, and examined whether these constructs mediated intervention effects on workplace sitting time at 3 and 12 months post-baseline.

Methods

Two hundred and thirty one office-based workers (14 worksites, single government employer) were randomised to intervention or control conditions by worksite. The intervention comprised organisational, environmental, and individual level elements. Participant characteristics and social-cognitive constructs (perceived behavioural control, barrier self-efficacy, perceived organisational norms and knowledge) were measured through a self-administered online survey at baseline, 3 months and 12 months. Workplace sitting time (min/8 h day) was measured with the activPAL3 device. Single multi-level mediation models were performed for each construct at both time points.

Results

There were significant intervention effects at 3 months on perceived behavioural control, barrier self-efficacy and perceived organisational norms. Effects on perceived organisational norms were not significant at 12 months. Perceived behavioural control significantly mediated intervention effects at 3 months, accounting for a small portion of the total effect (indirect effect: −8.6 min/8 h day, 95% CI: −18.5, −3.6 min; 7.5% of total effect). At 12 months, barrier self-efficacy significantly mediated the intervention effects on workplace sitting time (indirect effect: −10.3 min/8 h day, 95% CI: −27.3, −2.2; 13.9% of total effect). No significant effects were observed for knowledge at either time point.

Conclusions

Strategies that aim to increase workers’ perceived control and self-efficacy over their sitting time may be helpful components of sedentary behaviour interventions in the workplace. However, social-cognitive factors only partially explain variation in workplace sitting reduction. Understanding the importance of other levels of influence (particularly interpersonal and environmental) for initiating and maintaining workplace sedentary behaviour change will be informative for intervention development and refinement.

Trial registration

This study was prospectively registered with the Australian New Zealand Clinical Trials register (ACTRN12611000742976) on 15 July 2011.

Electronic supplementary material

The online version of this article (doi:10.1186/s12966-017-0483-1) contains supplementary material, which is available to authorized users.

Physical Activity and Sedentary Behavior in Breast and Colon Cancer Survivors Relative to Adults Without Cancer

OBJECTIVE

To assess differences in accelerometer-assessed moderate- to vigorous-intensity physical activity (MVPA), light-intensity physical activity, and sedentary time between cancer survivors and adults without cancer.

PATIENTS AND METHODS

Accelerometer data collected from 241 breast cancer survivors (ACCEL-Breast study, 2013) and 171 colon cancer survivors (ACCEL-Colon study, 2012-2013) were pooled with data collected from adults without cancer (Australian Diabetes, Obesity and Lifestyle accelerometer substudy, 2011-2012). Linear regression was used to estimate differences in physical activity and sedentary behavior levels between cancer survivors and adults without cancer, adjusted for potential confounding factors.

RESULTS

The mean MVPA was significantly higher among breast cancer survivors than among females who had not had cancer (29 vs 22 min/d; P<.001). Colon cancer survivors had significantly lower levels of light activity than did adults without cancer (311 vs 338 min/d; P<.001), more sedentary time (532 vs 507 min/d; P=.003), and more prolonged sedentary time (210 vs 184 min/d; P=.002).

CONCLUSION

Contrary to findings from previous research (based on self-reported physical activity), cancer survivors engaged in more (breast) or equivalent (colon) MVPA compared with adults without cancer. Differences between colon cancer survivors and adults without cancer for light activity and sedentary behavior highlight the importance of considering the full activity spectrum in the context of cancer control.

Living well after breast cancer randomized controlled trial protocol: evaluating a telephone-delivered weight loss intervention versus usual care in women following treatment for breast cancer

BACKGROUND

Obesity, physical inactivity and poor diet quality have been associated with increased risk of breast cancer-specific and all-cause mortality as well as treatment-related side-effects in breast cancer survivors. Weight loss intervention trials in breast cancer survivors have shown that weight loss is safe and achievable; however, few studies have examined the benefits of such interventions on a broad range of outcomes and few have examined factors important to translation (e.g. feasible delivery method for scaling up, assessment of sustained changes, cost-effectiveness). The Living Well after Breast Cancer randomized controlled trial aims to evaluate a 12-month telephone-delivered weight loss intervention (versus usual care) on weight change and a range of secondary outcomes including cost-effectiveness.

METHODS/DESIGN

Women (18-75 years; body mass index 25-45 kg/m2) diagnosed with stage I-III breast cancer in the previous 2 years are recruited from public and private hospitals and through the state-based cancer registry (target n = 156). Following baseline assessment, participants are randomized 1:1 to either a 12-month telephone-delivered weight loss intervention (targeting diet and physical activity) or usual care. Data are collected at baseline, 6-months (mid-intervention), 12-months (end-of-intervention) and 18-months (maintenance). The primary outcome is change in weight at 12-months. Secondary outcomes are changes in body composition, bone mineral density, cardio-metabolic and cancer-related biomarkers, metabolic health and chronic disease risk, physical function, patient-reported outcomes (quality of life, fatigue, menopausal symptoms, body image, fear of cancer recurrence) and behaviors (dietary intake, physical activity, sitting time). Data collected at 18-months will be used to assess whether outcomes achieved at end-of-intervention are sustained six months after intervention completion. Cost-effectiveness will be assessed, as will mediators and moderators of intervention effects.

DISCUSSION

This trial will provide evidence needed to inform the wide-scale provision of weight loss, physical activity and dietary interventions as part of routine survivorship care for breast cancer survivors.

TRIAL REGISTRATION

Australian and New Zealand Clinical Trial Registry (ANZCTR) - ACTRN12612000997853 (Registered 18 September 2012).

Identifying adults' valid waking wear time by automated estimation in activPAL data collected with a 24 h wear protocol

The activPAL monitor, often worn 24 h d^-1, provides accurate classification of sitting/reclining posture. Without validated automated methods, diaries-burdensome to participants and researchers-are commonly used to ensure measures of sedentary behaviour exclude sleep and monitor non-wear. We developed, for use with 24 h wear protocols in adults, an automated approach to classify activity bouts recorded in activPAL 'Events' files as 'sleep'/non-wear (or not) and on a valid day (or not). The approach excludes long periods without posture change/movement, adjacent low-active periods, and days with minimal movement and wear based on a simple algorithm. The algorithm was developed in one population (STAND study; overweight/obese adults 18-40 years) then evaluated in AusDiab 2011/12 participants (n  =  741, 44% men, aged  >35 years, mean  ±  SD 58.5  ±  10.4 years) who wore the activPAL3^™ (7 d, 24 h d^-1 protocol). Algorithm agreement with a monitor-corrected diary method (usual practice) was tested in terms of the classification of each second as waking wear (Kappa; κ) and the average daily waking wear time, on valid days. The algorithm showed 'almost perfect' agreement (κ  >  0.8) for 88% of participants, with a median kappa of 0.94. Agreement varied significantly (p  <  0.05, two-tailed) by age (worsens with age) but not by gender. On average, estimated wear time was approximately 0.5 h d^-1 higher than by the diary method, with 95% limits of agreement of approximately this amount  ±2 h d^-1. In free-living data from Australian adults, a simple algorithm developed in a different population showed 'almost perfect' agreement with the diary method for most individuals (88%). For several purposes (e.g. with wear standardisation), adopting a low burden, automated approach would be expected to have little impact on data quality. The accuracy for total waking wear time was less and algorithm thresholds may require adjustments for older populations.

Validity of an automated algorithm to identify waking and in-bed wear time in hip-worn accelerometer data collected with a 24 h wear protocol in young adults

Researchers are increasingly using 24 h accelerometer wear protocols. No automated method has been published that accurately distinguishes 'waking' wear time from other data ('in-bed', non-wear, invalid days) in young adults. This study examined the validity of an automated algorithm developed to achieve this for hip-worn Actigraph GT3X  +  60 s epoch data. We compared the algorithm against a referent method ('into-bed' and 'out-of-bed' times visually identified by two independent raters) and benchmarked against two published algorithms. All methods used the same non-wear rules. The development sample (n  =  11) and validation sample (n  =  95) were Australian young adults from the Raine pregnancy cohort (54% female), all aged approximately 22 years. The agreement with Rater 1 in each minute's classification (yes/no) of waking wear time was examined as kappa (κ), limited to valid days (⩾10 h waking wear time per day) according to the algorithm and Rater 1. Bland-Altman methods assessed agreement in daily totals of waking wear and in-bed wear time. Excellent agreement (κ  >  0.75) was obtained between the raters for 80% of participants (median κ  =  0.94). The algorithm showed excellent agreement with Rater 1 (κ  >  0.75) for 89% of participants and poor agreement (κ  <  0.40) for 1%. In this sample, the algorithm (median κ  =  0.86) performed better than algorithms validated in children (median κ  =  0.77) and adolescents (median κ  =  0.66). The mean difference (95% limits of agreement) between Rater 1 and the algorithm was 7 (-220, 234) min d^-1 for waking wear time on valid days and  -41 (-309, 228) min d^-1 for in-bed wear time. In this population, the automated algorithm's validity for identifying waking wear time was mostly good, not worse than inter-rater agreement, and better than the evaluated published alternatives. However, the algorithm requires improvement to better identify in-bed wear time.

Relative validity of a brief Fat and Fibre Behaviour Questionnaire in a population of overweight and obese breast cancer survivors: A note of caution

AIM

Dietary intake assessment is often difficult in research contexts because of time and resource constraints and participant burden. Valid, reliable and brief assessments of dietary behaviour are needed. Additionally, examination of instrument performance in a variety of populations is needed. This study assessed relative validity and responsiveness to change of the Fat and Fibre Behaviour Questionnaire (FFBQ) in a population of breast cancer survivors compared with dietary intake measured by 24-hour recalls.

METHODS

Data were collected at baseline and six months after baseline of a six-month, randomised controlled trial that evaluated a telephone-based behavioural weight loss intervention (n = 45) compared to usual care (n = 45) among overweight and obese breast cancer survivors. The FFBQ's total index, fat index and fibre index were assessed for relative validity against two 24-hour recalls (Pearson's correlations). Responsiveness to change was assessed as intervention group change divided by standard deviation of usual care group change.

RESULTS

Pearson's correlations of the fat index with fat intake measures ranged from -0.09 to -0.30 (P < 0.05) at baseline and from -0.19 to -0.28 (P < 0.05) for dietary change. Correlations of the fibre index with unadjusted and energy-adjusted fibre intake measures (0.25-0.32, P < 0.05) were significant at baseline only. Both the FFBQ and 24-hour recall were responsive to fat-related dietary changes and not responsive to fibre-related changes.

CONCLUSIONS

The FFBQ showed small to medium relative validity against 24-hour dietary recall for assessing fat and fibre dietary behaviours and changes in dietary fat, and was responsive to fat-related dietary changes in this population.

Associations of sedentary time and patterns of sedentary time accumulation with health-related quality of life in colorectal cancer survivors

Sedentary behavior (sitting/lying at low energy expenditure while awake) is emerging as an important risk factor that may compromise the health-related quality of life (HRQoL) of colorectal cancer (CRC) survivors. We examined associations of sedentary time with HRQoL in CRC survivors, 2–10 years post-diagnosis. In a cross-sectional study, stage I–III CRC survivors (n = 145) diagnosed (2002−2010) at Maastricht University Medical Center+, the Netherlands, wore the thigh-mounted MOX activity monitor 24 h/day for seven consecutive days. HRQoL outcomes were assessed by validated questionnaires (EORTC QLQ-C30, WHODAS II, Checklist Individual Strength, and Hospital Anxiety and Depression Scale). Confounder-adjusted linear regression models were used to estimate associations with HRQoL outcomes of MOX-derived total and prolonged sedentary time (in prolonged sedentary bouts ≥ 30 min), and usual sedentary bout duration, corrected for waking wear time. On average, participants spent 10.2 h/day sedentary (SD, 1.6), and 4.5 h/day in prolonged sedentary time (2.3). Mean usual sedentary bout duration was 27.3 min (SD, 16.8). Greater total and prolonged sedentary time, and longer usual sedentary bout duration were associated with significantly (P < 0.05) lower physical functioning, and higher disability and fatigue scores. Greater prolonged sedentary time and longer usual sedentary bout duration also showed significant associations with lower global quality of life and role functioning. Associations with distress and social functioning were non-significant. Sedentary time was cross-sectionally associated with poorer HRQoL outcomes in CRC survivors. Prospective studies are needed to investigate whether sedentary time reduction is a potential target for lifestyle interventions aiming to improve the HRQoL of CRC survivors.

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Sedentary time may negatively affect health outcomes in colorectal cancer survivors.

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Thigh-worn accelerometers provided objective and accurate estimates of sedentary time.

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Colorectal cancer survivors spent on average 10.2 h/day in sedentary time.

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Sedentary time was associated with worse quality of life, fatigue, and disability.

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Decreasing sedentary time could be a relevant target for lifestyle intervention.

Associations of Low- and High-Intensity Light Activity with Cardiometabolic Biomarkers

PURPOSE

Light-intensity physical activity (LIPA) accounts for much of adults' waking hours (≈40%) and substantially contributes to overall daily energy expenditure. Encompassing activity behaviors of low intensity (standing with little movement) to those of higher intensity (slow walking), LIPA is ubiquitous, yet little is known about how associations with health may vary depending on its intensity. We examined the associations of objectively assessed LIPA (categorized as either low LIPA [LLPA] or high LIPA [HLPA]) and moderate- to vigorous-intensity activity with cardiometabolic risk biomarkers.

METHODS

Cardiometabolic biomarkers were measured in 4614 US adults (47 ± 17 yr) who participated in the 2003-2004 and 2005-2006 National Health and Nutrition Examination Survey cycles. Multiple linear regression analyses examined the associations of three accelerometer-derived physical activity (SD increment per day) intensity categories (LLPA, 100-761 counts per minute; HLPA, 762-1951 counts per minute; moderate-intensity physical activity [MPA], 1952-5724 counts per minute; vigorous-intensity physical activity [VPA], ≥5725 counts per minute) with cardiometabolic biomarkers, adjusting for potential sociodemographic, behavioral, and medical confounders.

RESULTS

All intensities of physical activity were beneficially associated with waist circumference, C-reactive protein, triglycerides, fasting insulin, β-cell function, and insulin sensitivity (P < 0.05); only some activity intensities showed significant associations with systolic blood pressure (LLPA), body mass index, HDL cholesterol, fasting glucose, and 2-h plasma glucose (HLPA, MPA, and VPA). Generally, effect size increased with intensity of physical activity. Overall, further adjustment for waist circumference attenuated associations with MPA and VPA to a greater extent than associations with LLPA and HLPA.

CONCLUSIONS

The cross-sectional findings provide novel evidence for the potential benefits of increasing both LLPA and HLPA. They further reinforce the established importance of moderate- to vigorous-intensity activity, the mainstay of public health recommendations.

Organizational-Level Strategies With or Without an Activity Tracker to Reduce Office Workers' Sitting Time: Rationale and Study Design of a Pilot Cluster-Randomized Trial

Background

The office workplace is a key setting in which to address excessive sitting time and inadequate physical activity. One major influence on workplace sitting is the organizational environment. However, the impact of organizational-level strategies on individual level activity change is unknown. Further, the emergence of sophisticated, consumer-targeted wearable activity trackers that facilitate real-time self-monitoring of activity, may be a useful adjunct to support organizational-level strategies, but to date have received little evaluation in this workplace setting.

Objective

The aim of this study is to evaluate the feasibility, acceptability, and effectiveness of organizational-level strategies with or without an activity tracker on sitting, standing, and stepping in office workers in the short (3 months, primary aim) and long-term (12 months, secondary aim).

Methods

This study is a pilot, cluster-randomized trial (with work teams as the unit of clustering) of two interventions in office workers: organizational-level support strategies (eg, visible management support, emails) or organizational-level strategies plus the use of a waist-worn activity tracker (the LUMOback) that enables self-monitoring of sitting, standing, and stepping time and enables users to set sitting and posture alerts. The key intervention message is to ‘Stand Up, Sit Less, and Move More.’ Intervention elements will be implemented from within the organization by the Head of Workplace Wellbeing. Participants will be recruited via email and enrolled face-to-face. Assessments will occur at baseline, 3, and 12 months. Time spent sitting, sitting in prolonged (≥30 minute) bouts, standing, and stepping during work hours and across the day will be measured with activPAL3 activity monitors (7 days, 24 hours/day protocol), with total sitting time and sitting time during work hours the primary outcomes. Web-based questionnaires, LUMOback recorded data, telephone interviews, and focus groups will measure the feasibility and acceptability of both interventions and potential predictors of behavior change.

Results

Baseline and follow-up data collection has finished. Results are expected in 2016.

Conclusions

This pilot, cluster-randomized trial will evaluate the feasibility, acceptability, and effectiveness of two interventions targeting reductions in sitting and increases in standing and stepping in office workers. Few studies have evaluated these intervention strategies and this study has the potential to contribute both short and long-term findings.

Associations of Monitor-Assessed Activity with Performance-Based Physical Function

The purpose of this study was to investigate the cross-sectional associations of monitor-derived measures of sedentary time and physical activity with performance-based physical function in healthy Australian adults. Data from 602 participants (mean age 58.1±10.0 years; 58% female) from the 2011/12 wave of the Australian Diabetes, Obesity and Lifestyle (AusDiab3) study were analyzed. The thigh-worn activPAL3^™ monitor (7-days continuous wear) was used to derive time during waking hours spent: sitting/reclining; standing; and, stepping (overall, and separately as light [<3 METs] and moderate-to-vigorous physical activity [MVPA; ≥3 METs]), and number of sit-stand transitions. Associations of these (in hours/day, or 15 transitions/day) with physical function measures (8ft Timed Up and Go [TUG-8; log-transformed seconds] and Knee Extensor Strength [KES; kg]) were tested via linear regression, adjusting for confounders. Interactions by sex and age-category (<45; 45–54; 55–64; ≥65 years) were tested. In all participants, KES was significantly (p<0.05) associated with stepping and MVPA stepping only; none of the activity measures were associated with TUG-8. However, subgroup analysis revealed that in older adults (≥65 years), TUG-8 was associated with stepping and MVPA stepping (both p<0.05). All associations with sitting time, standing, sit-stand transition and sex interactions were not statistically significant. In summary, sitting time was not significantly associated with impaired muscle strength or gait/mobility in Australian adults aged 36–80 years, but light- to moderate activity (stepping) was positively associated with muscle strength, and gait/mobility in older adults aged ≥65 years. The direction of causation is not known and remains important to investigate considering the high prevalence of both poor function and limited activity in older age.

Objectively measured patterns of sedentary time and physical activity in young adults of the Raine study cohort

Background

To provide a detailed description of young adults’ sedentary time and physical activity.

Methods

384 young women and 389 young men aged 22.1 ± 0.6 years, all participants in the 22 year old follow-up of the Raine Study pregnancy cohort, wore Actigraph GT3X+ monitors on the hip for 24 h/day over a one-week period for at least one ‘valid’ day (≥10 h of waking wear time). Each minute epoch was classified as sedentary, light, moderate or vigorous intensity using 100 count and Freedson cut-points. Mixed models assessed hourly and daily variation; t-tests assessed gender differences.

Results

The average (mean ± SD) waking wear time was 15.0 ± 1.6 h/day, of which 61.4 ± 10.1 % was spent sedentary, 34.6 ± 9.1 % in light-, 3.7 ± 5.3 % in moderate- and, 0.3 ± 0.6 % in vigorous-intensity activity. Average time spent in moderate to vigorous activity (MVPA) was 36.2 ± 27.5 min/day. Relative to men, women had higher sedentary time, but also higher vigorous activity time. The ‘usual’ bout duration of sedentary time was 11.8 ± 4.5 min in women and 11.7 ± 5.2 min in men. By contrast, other activities were accumulated in shorter bout durations. There was large variation by hour of the day and by day of the week in both sedentary time and MVPA. Evenings and Sundays through Wednesdays tended to be particularly sedentary and/or inactive.

Conclusion

For these young adults, much of the waking day was spent sedentary and many participants were physically inactive (low levels of MVPA). We provide novel evidence on the time for which activities were performed and on the time periods when young adults were more sedentary and/or less active. With high sedentary time and low MVPA, young adults may be at risk for the life-course sequelae of these behaviours.

Electronic supplementary material

The online version of this article (doi:10.1186/s12966-016-0363-0) contains supplementary material, which is available to authorized users.

Accelerometer-derived sedentary and physical activity time in overweight/obese adults with type 2 diabetes: cross-sectional associations with cardiometabolic biomarkers

Objective

To examine the associations of sedentary time and physical activity with biomarkers of cardiometabolic health, including the potential collective impact of shifting mean time use from less- to more-active behaviours (cross-sectionally, using isotemporal substitution), in adults with type 2 diabetes.

Methods

Participants with overweight/obese body mass index (BMI; ≥25 kg/m²) (n = 279; 158 men, mean [SD] age = 58.2 [8.6] years) wore Actigraph GT1M accelerometers (waking hours; seven days) to assess moderate- to vigorous-intensity physical activity (MVPA), light-intensity activity, and sedentary time (segregated into non-prolonged [accumulated in bouts <30min] and prolonged [accumulated in bouts ≥30 min]). Cross-sectional associations with waist circumference, BMI, fasting blood (HbA_1c, glucose, triacylglycerols, high-density lipoprotein cholesterol), and blood pressure of these activity variables (30 min/day increments) were examined adjusted for confounders and wear then, if significant, examined using isotemporal substitution modelling.

Results

Waist circumference and BMI were significantly (p<0.05) associated with more prolonged sedentary time and less light-intensity activity. Light intensity activity was also significantly associated with lower fasting plasma glucose (relative rate: 0.98, 95% CI: 0.97, 1.00; p<0.05). No biomarker was significantly associated with non-prolonged sedentary time or MVPA. Lower mean prolonged sedentary time (−30 min/day) with higher mean light intensity time (+30 min/day) was significantly associated with lower waist circumference (β = −0.77, 95% CI: −1.33, −0.22 cm). Lower mean prolonged sedentary time (−30 min/day) with either 30 min/day higher mean non-prolonged sedentary time (β = −0.35, 95%CI: −0.70, −0.01 kg/m²) or light-intensity time (β = −0.36, −0.61, −0.11 kg/m²) was associated with significantly lower average BMI.

Conclusions

Significantly improved mean levels of waist circumference and BMI were observed when shifting time from prolonged sedentary to non-prolonged sedentary or light-intensity activity (cross-sectionally). Lifestyle interventions in overweight/obese adults with type 2 diabetes might consider targeting shifts in these non-MVPA activities to more rigorously evaluate their potential cardiometabolic benefit in this population.

Relationship between intervention dose and outcomes in living well with diabetes--a randomized trial of a telephone-delivered lifestyle-based weight loss intervention

PURPOSE

To examine associations of intervention dose with weight, physical activity, glycemic control, and diet outcomes in a randomized trial of a telephone counseling intervention.

DESIGN

Study design was a secondary analysis of intervention group.

SETTING

Study setting was primary care practices in a disadvantaged community in Australia.

SUBJECTS

Participants were adult patients with type 2 diabetes (n = 151).

INTERVENTION

Up to 27 telephone counseling calls were made during 18 months.

MEASURES

Intervention dose was assessed as the number of calls completed (in tertile categories). Primary outcomes were weight and HbA1c, and moderate to vigorous intensity physical activity via accelerometer. Secondary outcomes were dietary energy intake and diet quality via a validated questionnaire.

ANALYSIS

Analyses employed were bivariate associations of call completion with sociodemographics, and confounder-adjusted linear mixed models for associations of call completion with outcomes (multiple imputation of missing data).

RESULTS

Only previous diagnosis of depression/anxiety had a statistically significant (p = .008) association with call completion. Call completion was significantly associated with weight loss (p < .001) but not the other outcomes (p > .05). Relative to low call completion, mean weight loss (as a percentage of baseline weight) was greater in the high-call completion group by -3.3% (95% confidence interval, -5.0% to -1.5%).

CONCLUSION

Increased dose of intervention was associated with greater weight loss. More needs to be done to retain patients for the duration of weight loss and behavior change interventions, particularly those with diabetes and comorbid depression, who were the most difficult to engage.

Reallocating time to sleep, sedentary behaviors, or active behaviors: associations with cardiovascular disease risk biomarkers, NHANES 2005-2006

Sleep and sedentary and active behaviors are linked to cardiovascular disease risk biomarkers, and across a 24-hour day, increasing time in 1 behavior requires decreasing time in another. We explored associations of reallocating time to sleep, sedentary behavior, or active behaviors with biomarkers. Data (n = 2,185 full sample; n = 923 fasting subanalyses) from the cross-sectional 2005-2006 US National Health and Nutrition Examination Survey were analyzed. The amounts of time spent in sedentary behavior, light-intensity activity, and moderate-to-vigorous physical activity (MVPA) were derived from ActiGraph accelerometry (ActiGraph LLC, Pensacola, Florida), and respondents reported their sleep duration. Isotemporal substitution modeling indicated that, independent of potential confounders and time spent in other activities, beneficial associations (P < 0.05) with cardiovascular disease risk biomarkers were associated with the reallocation of 30 minutes/day of sedentary time with equal time of either sleep (2.2% lower insulin and 2.0% lower homeostasis model assessment of β-cell function), light-intensity activity (1.9% lower triglycerides, 2.4% lower insulin, and 2.2% lower homeostasis model assessment of β-cell function), or MVPA (2.4% smaller waist circumference, 4.4% higher high-density lipoprotein cholesterol, 8.5% lower triglycerides, 1.7% lower glucose, 10.7% lower insulin, and 9.7% higher homeostasis model assessment of insulin sensitivity. These findings provide evidence that MVPA may be the most potent health-enhancing, time-dependent behavior, with additional benefit conferred from light-intensity activities and sleep duration when reallocated from sedentary time.

Reducing office workers' sitting time: rationale and study design for the Stand Up Victoria cluster randomized trial

Background

Excessive time spent in sedentary behaviours (sitting or lying with low energy expenditure) is associated with an increased risk for type 2 diabetes, cardiovascular disease and some cancers. Desk-based office workers typically accumulate high amounts of daily sitting time, often in prolonged unbroken bouts. The Stand Up Victoria study aims to determine whether a 3-month multi-component intervention in the office setting reduces workplace sitting, particularly prolonged, unbroken sitting time, and results in improvements in cardio-metabolic biomarkers and work-related outcomes, compared to usual practice.

Methods/Design

A two-arm cluster-randomized controlled trial (RCT), with worksites as the unit of randomization, will be conducted in 16 worksites located in Victoria, Australia. Work units from one organisation (Department of Human Services, Australian Government) will be allocated to either the multi-component intervention (organisational, environmental [height-adjustable workstations], and individual behavioural strategies) or to a usual practice control group. The recruitment target is 160 participants (office-based workers aged 18–65 years and working at least 0.6 full time equivalent) per arm. At each assessment (0- [baseline], 3- [post intervention], and 12-months [follow-up]), objective measurement via the activPAL3 activity monitor will be used to assess workplace: sitting time (primary outcome); prolonged sitting time (sitting time accrued in bouts of ≥30 minutes); standing time; sit-to-stand transitions; and, moving time. Additional outcomes assessed will include: non-workplace activity; cardio-metabolic biomarkers and health indicators (including fasting glucose, lipids and insulin; anthropometric measures; blood pressure; and, musculoskeletal symptoms); and, work-related outcomes (presenteeism, absenteeism, productivity, work performance). Incremental cost-effectiveness and identification of both workplace and individual-level mediators and moderators of change will also be evaluated.

Discussion

Stand Up Victoria will be the first cluster-RCT to evaluate the effectiveness of a multi-component intervention aimed at reducing prolonged workplace sitting in office workers. Strengths include the objective measurement of activity and assessment of the intervention on markers of cardio-metabolic health. Health- and work-related benefits, as well as the cost-effectiveness of the intervention, will help to inform future occupational practice.

Trial registration

ACTRN1211000742976

Does an 'activity-permissive' workplace change office workers' sitting and activity time?

Introduction

To describe changes in workplace physical activity, and health-, and work-related outcomes, in workers who transitioned from a conventional to an ‘activity-permissive’ workplace.

Methods

A natural pre-post experiment conducted in Vancouver, Canada in 2011. A convenience sample of office-based workers (n=24, 75% women, mean [SD] age = 34.5 [8.1] years) were examined four months following relocation from a conventional workplace (pre) to a newly-constructed, purpose-built, movement-oriented physical environment (post). Workplace activity- (activPAL3-derived stepping, standing, and sitting time), health- (body composition and fasting cardio-metabolic blood profile), and work- (performance; job satisfaction) related outcomes were measured pre- and post-move and compared using paired t-tests.

Results

Pre-move, on average (mean [SD]) the majority of the day was spent sitting (364 [43.0] mins/8-hr workday), followed by standing (78.2 [32.1] mins/8-hr workday) and stepping (37.7 [15.6] mins/8-hr workday). The transition to the ‘activity-permissive’ workplace resulted in a significant increase in standing time (+18.5, 95% CI: 1.8, 35.2 mins/8-hr workday), likely driven by reduced sitting time (-19.7, 95% CI: -42.1, 2.8 mins/8-hr workday) rather than increased stepping time (+1.2, 95% CI: -6.2, 8.5 mins/8-hr workday). There were no statistically significant differences observed in health- or work-related outcomes.

Discussion

This novel, opportunistic study demonstrated that the broader workplace physical environment can beneficially impact on standing time in office workers. The long-term health and work-related benefits, and the influence of individual, organizational, and social factors on this change, requires further evaluation.

Active adults recall their physical activity differently to less active adults: test-retest reliability and validity of a physical activity survey

ISSUE ADDRESSED

This paper determined the test-retest reliability and criterion validity of a modified version of the Active Australia Survey (AAS) and whether these properties varied across participants' activity levels.

METHODS

Participants (n=63) responded to repeat administrations of the AAS and wore an accelerometer for 7 days. Analyses used Spearman's rho (rs,) or weighted kappa (κ) and Bland-Altman methods. Variation in mean difference and 95% limits of agreement (LOA) across average levels of activity were tested by linear regression.

RESULTS

Reliability correlations (rs; 95% confidence intervals (CI)) for minutes per week ranged from 0.40 (0.16, 0.59) to 0.80 (0.68, 0.87). For days per week, the agreement (κ; 95% CI) between administrations ranged from 0.43 (0.34, 0.73) to 0.83 (0.61, 0.93). There was a small mean difference between administrations (-8.46 moderate-vigorous minutes per week); 95% LOA widened as participants' average activity levels increased. Validity correlations (rs; 95% CI) for minutes per week ranged from 0.50 (0.28, 0.66) to 0.61 (0.43, 0.75). For days per week, the agreement (κ; 95% CI) ranged from 0.35 (0.10, 0.50) to 0.61 (0.29, 0.87). The mean difference between the AAS and accelerometer and 95% LOA both varied with participants' activity levels.

CONCLUSIONS

The reliability and validity of the modified AAS were better than those of previously published versions, but varied according to participants' activity levels. So what? In this study, participants who engaged in more activity had more measurement error than less active participants. This proportionality will have important implications for cross-sectional and intervention studies. This phenomenon needs to be examined for other self-reported physical activity measures.

Reducing sitting time in office workers: short-term efficacy of a multicomponent intervention

OBJECTIVE

To investigate the short-term efficacy of a multicomponent intervention to reduce office workers' sitting time.

METHODS

Allocation for this non-randomized controlled trial (n=43 participants; 56% women; 26-62 years; Melbourne, Australia) was by office floor, with data collected during July-September 2011. The 4-week intervention emphasized three key messages: "Stand Up, Sit Less, Move More" and comprised organizational, environmental, and individual elements. Changes in minutes/day at the workplace spent sitting (primary outcome), in prolonged sitting (sitting time accumulated in bouts ≥ 30 min), standing, and moving were objectively measured (activPAL3).

RESULTS

Relative to the controls, the intervention group significantly reduced workplace sitting time (mean change [95%CI]: -125 [-161, -89] min/8-h workday), with changes primarily driven by a reduction in prolonged sitting time (-73 [-108, -40] min/8-h workday). Workplace sitting was almost exclusively replaced by standing (+127 [+92, +162] min/8-h workday) with non-significant changes to stepping time (-2 [-7, +4] min/8-h workday) and number of steps (-70 [-350, 210]).

CONCLUSIONS

This multicomponent workplace intervention demonstrated that substantial reductions in sitting time are achievable in an office setting. Larger studies with longer timeframes are needed to assess sustainability of these changes, as well as their potential longer-term impacts on health and work-related outcomes.

Television viewing time and reduced life expectancy: a life table analysis

BACKGROUND

Prolonged television (TV) viewing time is unfavourably associated with mortality outcomes, particularly for cardiovascular disease, but the impact on life expectancy has not been quantified. The authors estimate the extent to which TV viewing time reduces life expectancy in Australia, 2008.

METHODS

The authors constructed a life table model that incorporates a previously reported mortality risk associated with TV time. Data were from the Australian Bureau of Statistics and the Australian Diabetes, Obesity and Lifestyle Study, a national population-based observational survey that started in 1999-2000. The authors modelled impacts of changes in population average TV viewing time on life expectancy at birth.

RESULTS

The amount of TV viewed in Australia in 2008 reduced life expectancy at birth by 1.8 years (95% uncertainty interval (UI): 8.4 days to 3.7 years) for men and 1.5 years (95% UI: 6.8 days to 3.1 years) for women. Compared with persons who watch no TV, those who spend a lifetime average of 6 h/day watching TV can expect to live 4.8 years (95% UI: 11 days to 10.4 years) less. On average, every single hour of TV viewed after the age of 25 reduces the viewer's life expectancy by 21.8 (95% UI: 0.3-44.7) min. This study is limited by the low precision with which the relationship between TV viewing time and mortality is currently known.

CONCLUSIONS

TV viewing time may be associated with a loss of life that is comparable to other major chronic disease risk factors such as physical inactivity and obesity.

Associations of physical activity and sitting time with the metabolic syndrome among Omani adults

Most findings on associations of physical activity and sedentary behavior with the metabolic syndrome are from developed countries; thus, we examined these relationships in adults from Sur, Oman. The Sur Healthy Lifestyle Survey (n = 1,335) used the World Health Organization (WHO) Stepwise methodology to assess chronic disease risk factors. Odds ratios for the metabolic syndrome were estimated using logistic regression models for domains of physical activity (work, transport, and leisure) and sitting time, and adjusted for confounding variables. Compared to their counterparts doing the least physical activity, lower odds of the metabolic syndrome were observed among those with higher work activity (0.60; 95% confidence interval (CI): 0.45, 0.80) and transport activity (0.69; 95% CI: 0.47, 1.00), but not leisure activity (0.91; 95% CI: 0.64, 1.32). Odds of the metabolic syndrome were higher in those who sat for ≥ 6 h daily compared to <3 h daily (odds ratio = 1.60, 95% CI: 1.04, 2.44), but not after further adjustment for physical activity. This is the first evidence from the Arabian Gulf on associations of physical activity and sitting time with the metabolic syndrome and provides empirical evidence to inform national physical activity guidelines, policies and programs.

Sit-stand workstations: a pilot intervention to reduce office sitting time

BACKGROUND

Sitting time is a prevalent health risk among office-based workers.

PURPOSE

To examine, using a pilot study, the efficacy of an intervention to reduce office workers' sitting time.

DESIGN

Quasi-experimental design with intervention-group participants recruited from a single workplace that was physically separate from the workplaces of comparison-group participants.

SETTING/PARTICIPANTS

Office workers (Intervention, n=18; Comparison, n=14) aged 20-65 years from Brisbane, Australia; data were collected and analyzed in 2011.

INTERVENTION

Installation of a commercially available sit-stand workstation.

MAIN OUTCOME MEASURES

Changes from baseline at 1-week and 3-month follow-up in time spent sitting, standing, and stepping at the workplace and during all waking time (activPAL3 activity monitor, 7-day observation). Fasting total cholesterol, high-density lipoprotein (HDL) cholesterol, triglycerides, and glucose levels were assessed at baseline and 3 months (Cholestech LDX Analyzer). Acceptability was assessed with a 5-point response scale (eight items).

RESULTS

The intervention group (relative to the comparison group) reduced sitting time at 1-week follow-up by 143 minutes/day at the workplace (95% CI= -184, -102) and 97 minutes/day during all waking time (95% CI= -144, -50). These effects were maintained at 3 months (-137 minutes/day and -78 minutes/day, respectively). Sitting was almost exclusively replaced by standing, with minimal changes to stepping time. Relative to the comparison group, the intervention group increased HDL cholesterol by an average of 0.26 mmol/L (95% CI=0.10, 0.42). Other biomarker differences were not significant. There was strong acceptability and preference for using the workstations, though some design limitations were noted.

CONCLUSIONS

This trial is the first with objective measurement and a comparison group to demonstrate that the introduction of a sit-stand workstation can substantially reduce office workers' sitting time both at the workplace and overall throughout the week.

Measuring older adults' sedentary time: reliability, validity, and responsiveness

PURPOSE

With evidence that prolonged sitting has deleterious health consequences, decreasing sedentary time is a potentially important preventive health target. High-quality measures, particularly for use with older adults, who are the most sedentary population group, are needed to evaluate the effect of sedentary behavior interventions. We examined the reliability, validity, and responsiveness to change of a self-report sedentary behavior questionnaire that assessed time spent in behaviors common among older adults: watching television, computer use, reading, socializing, transport and hobbies, and a summary measure (total sedentary time).

METHODS

In the context of a sedentary behavior intervention, nonworking older adults (n = 48, age = 73 ± 8 yr (mean ± SD)) completed the questionnaire on three occasions during a 2-wk period (7 d between administrations) and wore an accelerometer (ActiGraph model GT1M) for two periods of 6 d. Test-retest reliability (for the individual items and the summary measure) and validity (self-reported total sedentary time compared with accelerometer-derived sedentary time) were assessed during the 1-wk preintervention period, using Spearman (ρ) correlations and 95% confidence intervals (CI). Responsiveness to change after the intervention was assessed using the responsiveness statistic (RS).

RESULTS

Test-retest reliability was excellent for television viewing time (ρ (95% CI) = 0.78 (0.63-0.89)), computer use (ρ (95% CI) = 0.90 (0.83-0.94)), and reading (ρ (95% CI) = 0.77 (0.62-0.86)); acceptable for hobbies (ρ (95% CI) = 0.61 (0.39-0.76)); and poor for socializing and transport (ρ < 0.45). Total sedentary time had acceptable test-retest reliability (ρ (95% CI) = 0.52 (0.27-0.70)) and validity (ρ (95% CI) = 0.30 (0.02-0.54)). Self-report total sedentary time was similarly responsive to change (RS = 0.47) as accelerometer-derived sedentary time (RS = 0.39).

CONCLUSIONS

The summary measure of total sedentary time has good repeatability and modest validity and is sufficiently responsive to change suggesting that it is suitable for use in interventions with older adults.

Validity of self-reported measures of workplace sitting time and breaks in sitting time

PURPOSE

To understand the prevalence and potential health effect of prolonged workplace sedentary (sitting) time, valid measures are required. Here, we examined the criterion validity of a brief self-reported measure of workplace sitting time and breaks in sitting time.

METHODS

An interviewer-administered questionnaire was used to assess workplace sitting time (h·d(-1)) and breaks from sitting per hour at work in a convenience sample of 121 full-time workers (36% men, mean age = 37 yr, 53% office based). These self-reported measures were compared with accelerometer-derived sedentary time (hours per day, <100 counts per minute) and breaks per sedentary hour (number of times, ≥100 counts per minute) during work hours.

RESULTS

Self-reported sitting time was significantly correlated with accelerometer-derived sedentary time (Pearson r = 0.39, 95% confidence interval = 0.22-0.53), with an average sitting time 0.45 h·d(-1) higher than average sedentary time. Bland-Altman plots and regression analysis showed positive associations between the difference in sitting and sedentary time and the average of sitting and sedentary time (mean difference = -2.75 h + 0.47 × average sitting and sedentary time; limits of agreement = ±2.25 h·d(-1)). The correlation of self-reported breaks per sitting hour with accelerometer-derived breaks per sedentary hour was also statistically significant (Spearman rs = 0.26, 95% confidence interval = 0.11-0.44).

CONCLUSIONS

This study is the first to examine the criterion validity of an interviewer-administered questionnaire measure of workplace sitting time and breaks in sitting time using objective criterion measures. The workplace sitting measure has acceptable properties for use in observational studies concerned with sedentary behavior in groups of workers; however, the wide limits of agreement suggest caution in estimating individuals' sitting time with high precision. Using self-reported measures to capture patterns of workplace sitting (such as breaks in sitting time) requires further development.

Associations of objectively-assessed physical activity and sedentary time with depression: NHANES (2005-2006)

BACKGROUND

Studies provide conflicting evidence for the protective effects of moderate-to-vigorous-intensity physical activity on depression. Recent evidence suggests that sedentary behaviors may also be associated with depression.

PURPOSE

To examine the associations of accelerometer-derived moderate-to-vigorous-intensity physical activity and sedentary time with depression among a population-based sample.

METHODS

Cross-sectional study using 2,862 adults from the 2005-2006 US National Health and Nutrition Examination Survey. ActiGraph accelerometers were used to derive both moderate-to-vigorous-intensity physical activity and sedentary time.

RESULTS

Depression occurred in 6.8% of the sample. For moderate-to-vigorous-intensity physical activity, compared with those in quartile 1 (least active), significantly lower odds of depression were observed for those participants in quartiles 2 (OR=0.55, 95% CI, 0.34 to 0.89), 3 (OR=0.49, 95% CI, 0.26 to 0.93), and 4 (most active) (OR=0.37, 95% CI, 0.20 to 0.70) (p for trend p<0.01). In overweight/obese participants only, those in quartile 4 (most sedentary) had significantly higher odds for depression than those in quartile 1 (least sedentary) [quartile 3 vs 1 (OR=1.94, 95% CI, 1.01 to 3.68) and 4 vs 1 (OR=3.09, 95% CI, 1.25 to 7.68)].

CONCLUSION

The current study identified lower odds of depression were associated with increasing moderate-to-vigorous-intensity physical activity and decreasing sedentary time, at least within overweight/obese adults.

Relationship of television time with accelerometer-derived sedentary time: NHANES

PURPOSE

To examine the relationship of self-reported television (TV) viewing time with accelerometer-derived total sedentary time and to determine whether it differs by subgroup.

METHODS

Using data for adults (≥20 yr) from the 2003-2004 and 2005-2006 nationally representative US National Health and Nutrition Examination Surveys (NHANES; n=5738), linear regression models examined the associations of categories of self-reported TV viewing time (<1, 1, 2, 3, 4, and >5 h·d) with accelerometer-derived sedentary time (<100 counts per minute; h·d). Spearman ρ assessed the correlation between participants' rankings on the two measures. Analyses were stratified by gender, age, race/ethnicity, and, in the 2003-2004 NHANES cycle, by work status among working-aged adults (20-65 yr, n=2069).

RESULTS

TV viewing time was significantly associated with sedentary time, with positive associations for all gender, age, race/ethnicity groups, and for those not working or working part-time, but not for those in full-time work. However, correlations between rankings of the measures were only "fair" overall (ρ=0.22) and were similar for all gender and racial/ethnic groups and for those of mid- and older age but not for those of younger age (20-39 yr, ρ=0.05). In the working-aged subgroup, there was also a fair correlation between the measures for those not working (ρ=0.22) but no significant correlation for those in part-time (ρ=0.14) or full-time work (ρ=0.03).

CONCLUSIONS

Associations of TV viewing time with accelerometer-derived total sedentary time were statistically significant, but correlations were of only fair magnitude, and the strength of the relationship was not consistent across all population subgroups. These findings suggest that TV viewing time has an influence on overall sedentary time at a population level; however, measurement of sedentary time in other domains is also important.

A telephone-delivered physical activity and dietary intervention for type 2 diabetes and hypertension: does intervention dose influence outcomes?

PURPOSE

To examine associations of intervention dose with behavior change outcomes in a telephone counseling intervention for physical activity and dietary change.

DESIGN

Secondary analysis of intervention participants from a cluster-randomized controlled trial.

SETTING

Primary care practices in a disadvantaged community in Queensland, Australia.

SUBJECTS

Adult patients with type 2 diabetes or hypertension.

INTERVENTION

Patients (n = 228) received telephone counseling over a 12-month period. The initiation phase (1-4 months) consisted of up to 10 weekly or fortnightly calls; the maintenance-enhancement phase (5-12 months) consisted of up to eight monthly calls.

MEASURES

Intervention dose was defined as the number of calls completed in total and during each phase and was categorized into tertiles. Diet and physical activity were measured using validated self-report instruments.

ANALYSIS

Multivariate analyses of call completion and change in health behaviors.

RESULTS

Those completing a high number of calls were more likely to be female, white, older than 60 years, retired, and earning less than an average weekly Australian wage. Relative to low call completion, high completion during the maintenance-enhancement phase was associated with significantly greater (least squares mean [SE]) behavioral improvement for the following: total fat intake as percentage of calories (-3.58% [.74%]), saturated fat intake (-2.51% [.51%]), fiber intake (4.23 [1.20] g), and moderate-to-vigorous physical activity (187.82 [44.78] minutes).

CONCLUSION

Interventions of longer duration may be required to influence complex behaviors such as physical activity and fat and fiber intake.

Identifying sedentary time using automated estimates of accelerometer wear time

PURPOSE

The authors evaluated the accuracy of three automated accelerometer wear-time estimation algorithms against self-report. Direct effects on sedentary time (<100 cpm) and indirect effects on moderate-to-vigorous physical activity (MVPA, ≥1952 cpm) time were examined.

METHODS

A subsample from the 2004/2005 Australian Diabetes, Obesity and Lifestyle Study (n=148) completed activity logs and wore accelerometers for a total of 987 days. A published algorithm that allows movement within non-wear periods (Algorithm 1) was compared with one that allows less movement (Algorithm 2) or no movement (Algorithm 3). Implications for population estimates were examined using 2003/2004 US National Health and Nutrition Examination Survey data.

RESULTS

Mean difference per day between the criterion and estimated wear time was negligible for all three algorithms (≤11 min), but 95% limits of agreement (LOA) were wide (±≥2 h). Respectively, the algorithms (1, 2 and 3) misclassified sedentary time as non-wear on 31.9%, 19.4% and 18% of days and misclassified non-wear time as sedentary on 42.8%, 43.7% and 51.3% of days. Use of Algorithm 2 (compared with Algorithm 1) affected population estimates of sedentary time (higher by 20 min/day) but not MVPA time. Agreement between Algorithms 1 and 2 was good for MVPA time (mean difference -0.08, LOA: -2.08, 1.91 min), but not for wear time or sedentary time.

CONCLUSION

Accelerometer wear time can be estimated accurately on average; however, misclassification can be substantial for individuals. Algorithm choice affects estimates of sedentary time. Allowing very limited movement within non-wear periods can improve accuracy.