The reliability, validity, and stability of a measure of physical activity in the elderly

Validation of Proprietary and Novel Step-counting Algorithms for Individuals Ambulating With a Lower Limb Prosthesis

OBJECTIVE

To compare the accuracy and reliability of 10 different accelerometer-based step-counting algorithms for individuals with lower limb loss, accounting for different clinical characteristics and real-world activities.

DESIGN

Cross-sectional study.

SETTING

General community setting (ie, institutional research laboratory and community free-living).

PARTICIPANTS

Forty-eight individuals with a lower limb amputation (N=48) wore an ActiGraph (AG) wGT3x-BT accelerometer proximal to the foot of their prosthetic limb during labeled indoor/outdoor activities and community free-living.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Intraclass correlation coefficient (ICC), absolute and root mean square error (RMSE), and Bland Altman plots were used to compare true (manual) step counts to estimated step counts from the proprietary AG Default algorithm and low frequency extension filter, as well as from 8 novel algorithms based on continuous wavelet transforms, fast Fourier transforms (FFTs), and peak detection.

RESULTS

All algorithms had excellent agreement with manual step counts (ICC>0.9). The AG Default and FFT algorithms had the highest overall error (RMSE=17.81 and 19.91 steps, respectively), widest limits of agreement, and highest error during outdoor and ramp ambulation. The AG Default algorithm also had among the highest error during indoor ambulation and stairs, while a FFT algorithm had the highest error during stationary tasks. Peak detection algorithms, especially those using pre-set parameters with a trial-specific component, had among the lowest error across all activities (RMSE=4.07-8.99 steps).

CONCLUSIONS

Because of its simplicity and accuracy across activities and clinical characteristics, we recommend the peak detection algorithm with set parameters to count steps using a prosthetic-worn AG among individuals with lower limb loss for clinical and research applications.

Automated Estimation of Construction Equipment Emission Using Inertial Sensors and Machine Learning Models

The construction industry is one of the main producers of greenhouse gasses (GHG). With the looming consequences of climate change, sustainability measures including quantifying the amount of air pollution during a construction project have become an important project objective in the construction industry. A major contributor to air pollution during construction projects is the use of heavy equipment. Therefore, efficient operation and management can substantially reduce a project’s carbon footprint and other environmental harms. Using unintrusive and indirect methods to predict on-road vehicle emissions has been a widely researched topic. Nevertheless, the same is not true in the case of construction equipment. This paper describes the development and deployment of a framework that uses machine learning (ML) methods to predict the level of emissions from heavy construction equipment. Data is collected via an Internet of Things (IoT) approach with accelerometer and gyroscope sensors as data collection nodes. The developed framework was validated using an excavator performing real-world construction work. A portable emission measurement system (PEMS) was used along with the inertial sensors to record the amount of CO, NOX, CO2, SO2, and CH4 pollution emitted by the equipment. Different ML algorithms were developed and compared to identify the best model to predict emission levels from inertial sensors data. The results show that Random Forest with the coefficient of determination (R2) of 0.94, 0.91, and 0.94, and normalized root-mean-square error (NRMSE) of 4.25, 6.42, and 5.17 for CO, NOX, and CO2, respectively, was the best algorithm among different models evaluated in this study.

An mHealth-Facilitated Personalized Intervention for Physical Activity and Sleep in Community-Dwelling Older Adults

This randomized controlled pilot trial tested the preliminary effect of a 24-week mHealth-facilitated, personalized intervention on physical activity (PA) and sleep in 21 community-dwelling older adults. The intervention included a personalized exercise prescription, training, goal setting, and financial incentives. mHealth strategies, including self-monitoring, motivational messages, activity reminders, and phone coaching, were used to facilitate PA participation. PA and sleep were measured using actigraphy and questionnaires at baseline and 8-, 16-, and 24-week visits. Participants in the intervention group had lower objective PA levels at 24 weeks than at 8 and 16 weeks, although levels of PA remained higher than at baseline. Compared with the control group, the intervention increased PA at 8, 16, and 24 weeks; improved subjective sleep quality at 16 and 24 weeks; and increased actigraphy-measured sleep duration and sleep efficiency at 24 weeks. mHealth PA interventions may benefit PA and sleep in older adults. Strategies for maintaining long-term PA behavioral changes are needed.

Feasibility, Reliability, and Validity of the MotionWatch 8 to Evaluate Physical Activity Among Older Adults With and Without Cognitive Impairment in Assisted Living Settings

This study tested the feasibility, reliability, and validity of the MotionWatch 8 among assisted living residents with and without cognitive impairment. Data from the Dissemination and Implementation of Function Focused Care in Assisted Living Using the Evidence Integration Triangle study were used. The sample included 781 individuals from 85 facilities with a mean age of 89.48 (SD = 7.43) years. The majority were female (71%), White (97%), and overall (44%) had cognitive impairment. A total of 70% were willing to wear the MotionWatch 8. Reliability was supported as there was no difference in time spent in activity across three consecutive wear days. Validity was based on hypothesis testing, and function was associated with counts of activity at baseline (p = .001) and 4 months (p = .001). Those with cognitive impairment engaged in less physical activity (p = .04). The MotionWatch 8 is a useful option for measuring physical activity in older adults with and without cognitive impairment.

Association Between Objectively Measured Physical Activity and Opioid, Hypnotic, or Anticholinergic Medication Use in Older People: Data from the Physical Activity Cohort Scotland Study

BACKGROUND

Centrally acting medications cause cognitive slowing and incoordination, which could reduce older people's physical activity levels. This association has not been studied previously.

OBJECTIVES

The aim of this study was to examine the association between opioid, hypnotic and anticholinergic medication, and objectively measured physical activity, in a cohort of older people.

METHODS

We used data from the Physical Activity Cohort Scotland, a representative cohort of community-dwelling older people aged 65 years and over who were assessed at baseline and again 2-3 years later. Objective physical activity was measured using Stayhealthy RT3 accelerometers over 7 days. Baseline medication use (opioid use, hypnotic use, modified Anticholinergic Risk Scale [mARS]) was obtained from linked, routinely collected community prescribing records. Cross-sectional and longitudinal associations between baseline medication use and both baseline activity and change in activity over time were analysed using unadjusted and adjusted linear regression models.

RESULTS

Overall, 310 participants were included in the analysis; mean age 77 years (standard deviation 7). No association was seen between baseline use of any medication class and baseline physical activity levels in unadjusted or adjusted models. For change in activity over time, there was no difference between users and non-users of hypnotics or opioids. Higher anticholinergic burden was associated with a steeper decline in activity over the follow-up period (mARS 0: - 7051 counts/24 h/year; mARS 1-2: - 15,942 counts/24 h/year; mARS ≥ 3: - 19,544 counts/24 h/year; p = 0.03) and this remained robust to multiple adjustments.

CONCLUSION

Anticholinergic burden is associated with greater decline in objectively measured physical activity over time in older people, a finding not seen with hypnotic or opioid use.

Uso de test dual en ancianos institucionalizados con diferentes niveles de deterioro cognitivo. Estudio transversal

Introducción. El envejecimiento se ha relacionado con una mayor prevalencia de deterioro cognitivo. Las personas mayores con pérdida de funciones cognitivas presentan elevadas tasas de caídas. El desarrollo de las actividades de la vida diaria engloba dos o más tareas, siendo necesarios componentes cognitivos y motores.Objetivo. Analizar el rendimiento en pruebas sencillas y duales de sujetos en entorno residencial con diferentes grados de deterioro cognitivo.Materiales y métodos. Se realizó un estudio observacional de corte transversal en ancianos institucionalizados >65 años (n=80). Se evaluó el deterioro cognitivo con el Mini-Mental State Examination y se solicitó a los participantes realizar una tarea simple y dual en las pruebas Six-Minute Walk Test (6MWT) y Timed Up and Go (TUG).Resultados. Se distribuyeron los participantes en tres grupos. Se encontraron diferencias significativas entre los grupos con deterioro cognitivo y el grupo sin deterioro cognitivo para las pruebas 6MWT (p<0.05) y TUG (p<0.05), tanto en la tarea simple como en la tarea dual. Un peor rendimiento se asoció con una menor capacidad cognitiva.Conclusión. La severidad del deterioro cognitivo se encuentra relacionada con el desempeño en las tareas duales.

Mobile Phone-Based Measures of Activity, Step Count, and Gait Speed: Results From a Study of Older Ambulatory Adults in a Naturalistic Setting

Background

Cellular mobile telephone technology shows much promise for delivering and evaluating healthcare interventions in cost-effective manners with minimal barriers to access. There is little data demonstrating that these devices can accurately measure clinically important aspects of individual functional status in naturalistic environments outside of the laboratory.

Objective

The objective of this study was to demonstrate that data derived from ubiquitous mobile phone technology, using algorithms developed and previously validated by our lab in a controlled setting, can be employed to continuously and noninvasively measure aspects of participant (subject) health status including step counts, gait speed, and activity level, in a naturalistic community setting. A second objective was to compare our mobile phone-based data against current standard survey-based gait instruments and clinical physical performance measures in order to determine whether they measured similar or independent constructs.

Methods

A total of 43 ambulatory, independently dwelling older adults were recruited from Nebraska Medicine, including 25 (58%, 25/43) healthy control individuals from our Engage Wellness Center and 18 (42%, 18/43) functionally impaired, cognitively intact individuals (who met at least 3 of 5 criteria for frailty) from our ambulatory Geriatrics Clinic. The following previously-validated surveys were obtained on study day 1: (1) Late Life Function and Disability Instrument (LLFDI); (2) Survey of Activities and Fear of Falling in the Elderly (SAFFE); (3) Patient Reported Outcomes Measurement Information System (PROMIS), short form version 1.0 Physical Function 10a (PROMIS-PF); and (4) PROMIS Global Health, short form version 1.1 (PROMIS-GH). In addition, clinical physical performance measurements of frailty (10 foot Get up and Go, 4 Meter walk, and Figure-of-8 Walk [F8W]) were also obtained. These metrics were compared to our mobile phone-based metrics collected from the participants in the community over a 24-hour period occurring within 1 week of the initial assessment.

Results

We identified statistically significant differences between functionally intact and frail participants in mobile phone-derived measures of percent activity (P=.002, t test), active versus inactive status (P=.02, t test), average step counts (P<.001, repeated measures analysis of variance [ANOVA]) and gait speed (P<.001, t test). In functionally intact individuals, the above mobile phone metrics assessed aspects of functional status independent (Bland-Altman and correlation analysis) of both survey- and/or performance battery-based functional measures. In contrast, in frail individuals, the above mobile phone metrics correlated with submeasures of both SAFFE and PROMIS-GH.

Conclusions

Continuous mobile phone-based measures of participant community activity and mobility strongly differentiate between persons with intact functional status and persons with a frailty phenotype. These measures assess dimensions of functional status independent of those measured using current validated questionnaires and physical performance assessments to identify functional compromise. Mobile phone-based gait measures may provide a more readily accessible and less-time consuming measure of gait, while further providing clinicians with longitudinal gait measures that are currently difficult to obtain.

Systemic effects of chronic obstructive pulmonary disease in young-old adults' life-space mobility

PURPOSE

The objective was to assess whether dyspnea, peripheral muscle strength and the level of physical activity are correlated with life-space mobility of older adults with COPD.

PATIENTS AND METHODS

Sixty patients over 60 years of age (40 in the COPD group and 20 in the control group) were included. All patients were evaluated for lung function (spirometry), life-space mobility (University of Alabama at Birmingham Study of Aging Life-Space Assessment), dyspnea severity (Modified Dyspnea Index), peripheral muscle strength (handgrip dynamometer), level of physical activity and number of daily steps (accelerometry). Groups were compared using unpaired t-test. Pearson's correlation was used to test the association between variables.

RESULTS

Life-space mobility (60.41±16.93 vs 71.07±16.28 points), dyspnea (8 [7-9] vs 11 [10-11] points), peripheral muscle strength (75.16±14.89 vs 75.50±15.13 mmHg), number of daily steps (4,865.4±2,193.3 vs 6,146.8±2,376.4 steps), and time spent in moderate to vigorous activity (197.27±146.47 vs 280.05±168.95 minutes) were lower among COPD group compared to control group (p<0.05). The difference was associated with the lower mobility of COPD group in the neighborhood.

CONCLUSION

Life-space mobility is decreased in young-old adults with COPD, especially at the neighborhood level. This impairment is associated to higher dyspnea, peripheral muscle weakness and the reduced level of physical activity.

Factors associated with change in objectively measured physical activity in older people - data from the physical activity cohort Scotland study

Background

Cross-sectional relationships between physical activity and health have been explored extensively, but less is known about how physical activity changes with time in older people. The aim of this study was to assess baseline predictors of how objectively measured physical activity changes with time in older people.

Methods

Longitudinal cohort study using data from the Physical Activity Cohort Scotland. A sample of community-dwelling older people aged 65 and over were recruited in 2009–2011, then followed up 2–3 years later. Physical activity was measured using Stayhealthy RT3 accelerometers over 7 days. Other data collected included baseline comorbidity, health-related quality of life (SF-36), extended Theory of Planned Behaviour Questionnaire and Social Capital Module of the General Household Survey. Associations between follow-up accelerometer counts and baseline predictors were analysed using a series of linear regression models, adjusting for baseline activity levels and follow-up time.

Results

Follow up data were available for 339 of the original 584 participants. The mean age was 77 years, 185 (55%) were female and mean follow up time was 26 months. Mean activity counts fell by between 2% per year (age < =80, deprivation decile 5–10) and 12% per year (age > 80, deprivation decile 5–10) from baseline values. In univariate analysis age, sex, deprivation decile, most SF-36 domains, most measures of social connectedness, most measures from the extended Theory of Planned Behaviour, hypertension, diabetes mellitus, chronic pain and depression score were significantly associated with adjusted activity counts at follow-up. In multivariate regression age, satisfactory friend network, SF-36 physical function score, and the presence of diabetes mellitus were independent predictors of activity counts at follow up after adjustment for baseline count and duration of follow up.

Conclusions

Health status and social connectedness, but not extended Theory of Planned Behaviour measures, independently predicted changes in physical activity in community dwelling older people.

Electronic supplementary material

The online version of this article (doi:10.1186/s12877-017-0578-1) contains supplementary material, which is available to authorized users.

Correlates of Physical Functioning and Performance Across the Spectrum of Kidney Function

The aim of this study was to determine the extent to which poor physical functioning, low participation in physical activity, and muscle atrophy observed among patients on hemodialysis are evident in the earlier stages of chronic kidney disease (CKD). We enrolled adults in three groups: no CKD, Stages 3 to 4 CKD, and hemodialysis. Outcomes measured were physical activity, muscle size, thigh muscle strength, physical performance, and self-reported physical function. Patients with CKD had muscle area intermediate between the no CKD and hemodialysis groups, but they had low levels of physical activity that were similar to the hemodialysis group. Physical activity and muscle size were significantly associated with all outcomes. Kidney function was not significantly associated with muscle strength or physical performance after adjustment for physical activity and muscle size. In conclusion, interventions aimed to increase muscle mass and energy expenditure might have an impact on improving physical function of CKD patients.

Measurement of daily physical activity using the SenseWear Armband: Compliance, comfort, adverse side effects and usability

Little is known about the acceptability of wearing physical activity-monitoring devices. This study aimed to examine the compliance, comfort, incidence of adverse side effects, and usability when wearing the SenseWear Armband (SWA) for daily physical activity assessment. In a prospective study, 314 participants (252 people with COPD, 36 people with a dust-related respiratory disease and 26 healthy age-matched people) completed a purpose-designed questionnaire following a 7-day period of wearing the SWA. Compliance, comfort levels during the day and night, adverse side effects and ease of using the device were recorded. Non-compliance with wearing the SWA over 7 days was 8%. The main reasons for removing the device were adverse side effects and discomfort. The SWA comfort level during the day was rated by 11% of participants as uncomfortable/very uncomfortable, with higher levels of discomfort reported during the night (16%). Nearly half of the participants (46%) experienced at least one adverse skin irritation side effect from wearing the SWA including itchiness, skin irritation and rashes, and/or bruising. Compliance with wearing the SWA for measurement of daily physical activity was found to be good, despite reports of discomfort and a high incidence of adverse side effects.

Acceptance of Commercially Available Wearable Activity Trackers Among Adults Aged Over 50 and With Chronic Illness: A Mixed-Methods Evaluation

Background

Physical inactivity and sedentary behavior increase the risk of chronic illness and death. The newest generation of “wearable” activity trackers offers potential as a multifaceted intervention to help people become more active.

Objective

To examine the usability and usefulness of wearable activity trackers for older adults living with chronic illness.

Methods

We recruited a purposive sample of 32 participants over the age of 50, who had been previously diagnosed with a chronic illness, including vascular disease, diabetes, arthritis, and osteoporosis. Participants were between 52 and 84 years of age (mean 64); among the study participants, 23 (72%) were women and the mean body mass index was 31 kg/m². Participants tested 5 trackers, including a simple pedometer (Sportline or Mio) followed by 4 wearable activity trackers (Fitbit Zip, Misfit Shine, Jawbone Up 24, and Withings Pulse) in random order. Selected devices represented the range of wearable products and features available on the Canadian market in 2014. Participants wore each device for at least 3 days and evaluated it using a questionnaire developed from the Technology Acceptance Model. We used focus groups to explore participant experiences and a thematic analysis approach to data collection and analysis.

Results

Our study resulted in 4 themes: (1) adoption within a comfort zone; (2) self-awareness and goal setting; (3) purposes of data tracking; and (4) future of wearable activity trackers as health care devices. Prior to enrolling, few participants were aware of wearable activity trackers. Most also had been asked by a physician to exercise more and cited this as a motivation for testing the devices. None of the participants planned to purchase the simple pedometer after the study, citing poor accuracy and data loss, whereas 73% (N=32) planned to purchase a wearable activity tracker. Preferences varied but 50% felt they would buy a Fitbit and 42% felt they would buy a Misfit, Jawbone, or Withings. The simple pedometer had a mean acceptance score of 56/95 compared with 63 for the Withings, 65 for the Misfit and Jawbone, and 68 for the Fitbit. To improve usability, older users may benefit from devices that have better compatibility with personal computers or less-expensive Android mobile phones and tablets, and have comprehensive paper-based user manuals and apps that interpret user data.

Conclusions

For older adults living with chronic illness, wearable activity trackers are perceived as useful and acceptable. New users may need support to both set up the device and learn how to interpret their data.

Optimizing physical activity among older adults post trauma: Overcoming system and patient challenges

BACKGROUND

By 2050 it is anticipated that close to half (40%) of all trauma patients will be over the age of 65. Recovery for these individuals is more complicated than among younger individuals. Early mobilization has been shown to improve outcomes. Unfortunately, there are many challenges to early mobilization. The Function Focused Care Intervention was developed to overcome these challenges.

PURPOSE

The purpose of this paper was to describe the initial recruitment of the first 25 participants and delineate the challenges and successes associated with implementation of this intervention.

RESULTS

Overall recruitment rates were consistent with other studies and the intervention was implemented as intended. Most patients were female, white and on average 79 years of age. Optimizing physical activity of patients was a low priority for the nurses with patient safety taking precedence. Patients spent most of the time in bed. Age, depression and tethering were the only factors that were associated with physical activity and functional outcomes of patients.

CONCLUSION

Ongoing work is needed to keep patients physically active in the immediate post trauma recovery period.

Impact of care settings on residents' functional and psychosocial status, physical activity and adverse events

BACKGROUND

Internationally, as the number of older adults increases, different types of care settings are evolving to address the care needs of this growing group of individuals.

AIMS AND OBJECTIVES

The purpose of this study was to describe and compare clinical outcomes of residents with moderate to severe cognitive impairment living in residential care facilities (RCFs) and nursing homes (NHs).

DESIGN

This was a secondary data analysis that included data from two studies testing a Function-Focused Care for Cognitively Impaired (FFC-CI) Intervention.

METHODS

A total of 96 participants were from RCFs and 103 were from NHs. Change scores over a 6-month period in RCF and NH residents were evaluated using a multivariate analysis of variance.

RESULTS

Residential care facilities residents had more agitation, better function and engaged in approximately twice as much physical activity as those in NH settings at baseline. Controlling for treatment status and baseline differences, over 6 months, RCF residents showed a decrease of -22.77 ± 41.47 kilocalories used in 24 hours while those in NHs increased to a mean of 10.49 ± 33.65 kilocalories used. With regard to function, residents in RCFs declined 10.97 ± 18.35 points on the Barthel Index, while those in NHs increased 10.18 ± 19.56 points.

CONCLUSIONS

In this sample, NH residents were more likely to be African American, had more comorbidities, less cognitive impairment, engaged in less physical activity, were more impaired functionally and had less agitation than those in RCFs. Controlling for treatment group status and baseline differences in comorbidities, cognitive status and race, residents in RCFs declined more in terms of functional and physical activity over a 6-month period.

IMPLICATIONS FOR PRACTICE

Ongoing research and clinical work is needed to understand the impact of care settings on clinical outcomes.

Adaptive sports technology and biomechanics: prosthetics

With the technologic advances in medicine and an emphasis on maintaining physical fitness, the population of athletes with impairments is growing. It is incumbent upon health care practitioners to make every effort to inform these individuals of growing and diverse opportunities and to encourage safe exercise and athletic participation through counseling and education. Given the opportunities for participation in sports for persons with a limb deficiency, the demand for new, innovative prosthetic designs is challenging the clinical and technical expertise of the physician and prosthetist. When generating a prosthetic prescription, physicians and prosthetists should consider the needs and preferences of the athlete with limb deficiency, as well as the functional demands of the chosen sporting activity. The intent of this article is to provide information regarding the current advancements in the adaptive sports technology and biomechanics in the field of prosthetics, and to assist clinicians and their patients in facilitating participation in sporting activities.

Reliability and validity of the Japanese version of the short questionnaire to assess health-enhancing physical activity (SQUASH) scale in older adults

[Purpose] We tested the reliability and validity of the Japanese version of the Short Questionnaire to Assess Health-enhancing Physical Activity scale in asymptomatic older adults and sought to confirm discriminator validity in women with osteoarthritis. [Subjects] The participants included an asymptomatic comparison group (men and women) and women with knee or hip osteoarthritis. [Methods] The test-retest method was used to assess reliability. The International Physical Activity Questionnaire was chosen to assess criterion-related validity. Discriminator validity was assessed by comparing the asymptomatic and osteoarthritis groups. [Results] Mean age for the asymptomatic groups was 63 ± 6 years for men (n = 23) and 61 ± 7 years for women (n = 51), and it was 63 ± 9 years for the osteoarthritis group (n = 32). The total score and scores for all items, except for heavy housework items, were significantly correlated with the retest. Criterion-related validity showed significantly weak to moderate correlations between the respective scale categories. For discriminator validity, the total scores and scores for bicycle commuting, light housework, and three leisure items differed significantly between the asymptomatic and osteoarthritis groups. [Conclusion] The Short Questionnaire to Assess Health-enhancing Physical Activity scale is a reliable and valid measure in asymptomatic older adults, and can discriminate between osteoarthritic and asymptomatic women.

Does a Nintendo Wii exercise program provide similar exercise demands as a traditional pulmonary rehabilitation program in adults with COPD?

BACKGROUND AND AIMS

The chronic obstructive pulmonary disease (COPD) population can experience lower activity and fitness levels than the non-COPD population. The Nintendo Wii may be an appropriate at-home training device for the COPD population, which could be used as a supplement for a pulmonary rehabilitation program. This study was a randomized, within-subject, cross-over study involving 10 adults with COPD previously enrolled in St Paul's Hospital's pulmonary rehabilitation program. This study attempted to determine if specific Wii activities resulted in similar energy expenditures to that of a more traditional pulmonary rehabilitation activity.

METHODS

Participants completed two 15-min exercise interventions in a single session, with a washout period of 30 min in-between. The interventions were an experimental Wii intervention and a traditional treadmill intervention.

RESULTS

There was no significant difference in total energy expenditure between the two 15-min exercise interventions [mean difference 36.3 joules; 95% confidence interval (CI): 31.4, 104]. There was no significant difference in heart rate (mean difference -0.167 beats per minute; 95% CI: -4.83, 4.50), rating of perceived exertion (mean difference 0.100; 95% CI: -0.416, 0.616) and Borg dyspnea scale (mean difference 0.267; 95% CI: -0.004, 0.537) between the two 15-min exercise interventions. There was a significant difference in SpO2 between the two 15-min exercise interventions (Wii intervention mean difference 2.33% > treadmill intervention; 95% CI: 1.52, 3.15).

CONCLUSION

Gaming technology can provide an exercise program that has similar cardiovascular demands to traditional pulmonary rehabilitation programs for patients with COPD. Further research is necessary to address feasibility and long-term adherence.

Accelerometer-based measures in physical activity surveillance: current practices and issues

OBJECTIVE

Self-reports of physical activity (PA) have been the mainstay of measurement in most non-communicable disease (NCD) surveillance systems. To these, other measures are added to summate to a comprehensive PA surveillance system. Recently, some national NCD surveillance systems have started using accelerometers as a measure of PA. The purpose of this paper was specifically to appraise the suitability and role of accelerometers for population-level PA surveillance.

METHODS

A thorough literature search was conducted to examine aspects of the generalisability, reliability, validity, comprehensiveness and between-study comparability of accelerometer estimates, and to gauge the simplicity, cost-effectiveness, adaptability and sustainability of their use in NCD surveillance.

CONCLUSIONS

Accelerometer data collected in PA surveillance systems may not provide estimates that are generalisable to the target population. Accelerometer-based estimates have adequate reliability for PA surveillance, but there are still several issues associated with their validity. Accelerometer-based prevalence estimates are largely dependent on the investigators' choice of intensity cut-off points. Maintaining standardised accelerometer data collections in long-term PA surveillance systems is difficult, which may cause discontinuity in time-trend data. The use of accelerometers does not necessarily produce useful between-study and international comparisons due to lack of standardisation of data collection and processing methods. To conclude, it appears that accelerometers still have limitations regarding generalisability, validity, comprehensiveness, simplicity, affordability, adaptability, between-study comparability and sustainability. Therefore, given the current evidence, it seems that the widespread adoption of accelerometers specifically for large-scale PA surveillance systems may be premature.

Dog ownership and physical activity in later life: a cross-sectional observational study

OBJECTIVE

To examine whether dog ownership amongst community dwelling older adults (≥ 65 years) is associated with objectively measured physical activity (PA).

METHODS

We used data from the Physical Activity Cohort Scotland (PACS) which consists of 547 people aged 65 and over, resident in the community in Tayside, Scotland. The data was collected in 2009-2011. We assessed whether dog ownership is associated with objectively measured physical activity (accelerometry counts).

RESULTS

The physical activity (PA) counts of 547 older people (mean age 79 (standard deviation (SD) 8 years, 54% female) were analysed. Linear mixed models showed that dog ownership was positively related to higher PA levels. This positive relationship remained after controlling for a large number of individual and contextual variables, including attitude towards exercise, physical activity intention and history of physical activity. Dog owners were found to be 12% more active (21,875 counts, 95% Confidence Interval (CI): 2810 to 40,939, p<0.05) than non-dog owners.

CONCLUSION

Dog ownership is associated with physical activity in later life. Interventions to increase activity amongst older people might usefully attempt to replicate elements of the dog ownership experience.

Association of day length and weather conditions with physical activity levels in older community dwelling people

BACKGROUND

Weather is a potentially important determinant of physical activity. Little work has been done examining the relationship between weather and physical activity, and potential modifiers of any relationship in older people. We therefore examined the relationship between weather and physical activity in a cohort of older community-dwelling people.

METHODS

We analysed prospectively collected cross-sectional activity data from community-dwelling people aged 65 and over in the Physical Activity Cohort Scotland. We correlated seven day triaxial accelerometry data with daily weather data (temperature, day length, sunshine, snow, rain), and a series of potential effect modifiers were tested in mixed models: environmental variables (urban vs rural dwelling, percentage of green space), psychological variables (anxiety, depression, perceived behavioural control), social variables (number of close contacts) and health status measured using the SF-36 questionnaire.

RESULTS

547 participants, mean age 78.5 years, were included in this analysis. Higher minimum daily temperature and longer day length were associated with higher activity levels; these associations remained robust to adjustment for other significant associates of activity: age, perceived behavioural control, number of social contacts and physical function. Of the potential effect modifier variables, only urban vs rural dwelling and the SF-36 measure of social functioning enhanced the association between day length and activity; no variable modified the association between minimum temperature and activity.

CONCLUSIONS

In older community dwelling people, minimum temperature and day length were associated with objectively measured activity. There was little evidence for moderation of these associations through potentially modifiable health, environmental, social or psychological variables.

Direct and indirect measurement of physical activity in older adults: a systematic review of the literature

BACKGROUND

Due to physiological and cognitive changes that occur with aging, accurate physical activity (PA) measurement in older adults represents a unique challenge. The primary purpose of this study was to systematically review measures of PA and their use and appropriateness with older adults. A secondary aim was to determine the level of agreement between PA measures in older adults.

METHODS

Literature was identified through electronic databases. Studies were eligible if they examined the correlation and/or agreement between at least 2 measures, either indirect and/or direct, of PA in older adults (> 65 years of age).

RESULTS

Thirty-six studies met eligibility criteria. The indirect and direct measures of PA across the studies differed widely in their ability to address the key dimensions (i.e., frequency, intensity, time, type) of PA in older adults. The average correlation between indirect and direct measures was moderate (r=0.38). The correlation between indirect and other indirect measures (r=0.29) was weak, while correlations between direct measures with other direct measures were high (real world: r= 0.84; controlled settings: r=0.92). Agreement was strongest between direct PA measures with other direct measures in both real world and laboratory settings. While a clear trend regarding the agreement for mean differences between other PA measures (i.e., direct with indirect, indirect with indirect) did not emerge, there were only a limited number of studies that reported comparable units.

CONCLUSIONS

Despite the lack of a clear trend regarding the agreement between PA measures in older adults, the findings underscore the importance of valid, accurate and reliable measurement. To advance this field, researchers will need to approach the assessment of PA in older adults in a more standardized way (i.e., consistent reporting of results, consensus over cut-points and epoch lengths, using appropriate validation tools). Until then researchers should be cautious when choosing measures for PA that are appropriate for their research questions and when comparing PA levels across various studies.

Validity of activity monitors in health and chronic disease: a systematic review

The assessment of physical activity in healthy populations and in those with chronic diseases is challenging. The aim of this systematic review was to identify whether available activity monitors (AM) have been appropriately validated for use in assessing physical activity in these groups. Following a systematic literature search we found 134 papers meeting the inclusion criteria; 40 conducted in a field setting (validation against doubly labelled water), 86 in a laboratory setting (validation against a metabolic cart, metabolic chamber) and 8 in a field and laboratory setting. Correlation coefficients between AM outcomes and energy expenditure (EE) by the criterion method (doubly labelled water and metabolic cart/chamber) and percentage mean differences between EE estimation from the monitor and EE measurement by the criterion method were extracted. Random-effects meta-analyses were performed to pool the results across studies where possible. Types of devices were compared using meta-regression analyses. Most validation studies had been performed in healthy adults (n = 118), with few carried out in patients with chronic diseases (n = 16). For total EE, correlation coefficients were statistically significantly lower in uniaxial compared to multisensor devices. For active EE, correlations were slightly but not significantly lower in uniaxial compared to triaxial and multisensor devices. Uniaxial devices tended to underestimate TEE (−12.07 (95%CI; -18.28 to −5.85) %) compared to triaxial (−6.85 (95%CI; -18.20 to 4.49) %, p = 0.37) and were statistically significantly less accurate than multisensor devices (−3.64 (95%CI; -8.97 to 1.70) %, p<0.001). TEE was underestimated during slow walking speeds in 69% of the lab validation studies compared to 37%, 30% and 37% of the studies during intermediate, fast walking speed and running, respectively. The high level of heterogeneity in the validation studies is only partly explained by the type of activity monitor and the activity monitor outcome. Triaxial and multisensor devices tend to be more valid monitors. Since activity monitors are less accurate at slow walking speeds and information about validated activity monitors in chronic disease populations is lacking, proper validation studies in these populations are needed prior to their inclusion in clinical trials.

Alternative scoring for Physical Activity Scale for the Elderly (PASE)

BACKGROUND

Studies assessing physical functioning with the Physical Activity Scale for the Elderly (PASE) should be aware that the instrument may be age and culture insensitive.

OBJECTIVES

To asses "classical" PASE scoring in a sample of aged (mean age 74) Mexican origin Latinos in the Southwestern United States and provide a new scoring algorithm.

METHOD

Information from a cross sectional study of 2438 community-dwelling minority subjects who completed the PASE scale was scored with the classical and a new scoring approach to compare their similarity and predictive power on three items of functional ability.

RESULTS

The classical and new scoring procedures for PASE items render different total scores.

CONCLUSION

The classical approach for scoring PASE in aged minorities may fail to capture the age and culture insensitivity of the instrument. The new approach, or a derivation of it, should be used to compute the total PASE score for minority aged populations as further research continues.

Treadmill gait speeds correlate with physical activity counts measured by cell phone accelerometers

A number of important health-related outcomes are directly related to a person's ability to maintain normal gait speed. We hypothesize that cellular telephones may be repurposed to measure this important behavior in a noninvasive, continuous, precise, and inexpensive manner. The purpose of this study was to determine if physical activity (PA) counts collected by cell phone accelerometers could measure treadmill gait speeds. We also assessed how cell phone placement influenced treadmill gait speed measures. Participants included 55 young, middle-aged, and older community-dwelling men and women. We placed cell phones as a pendant around the neck, and on the left and right wrist, hip, and ankle. Subjects then completed an individualized treadmill protocol, alternating 1 min rest periods with 5 min of walking at different speeds (0.3-11.3 km/h; 0.2-7 mi/h). No persons were asked to walk at speeds faster than what they would achieve during day-to-day life. PA counts were calculated from all sensor locations. We built linear mixed statistical models of PA counts predicted by treadmill speeds ranging from 0.8 to 6.4 km/h (0.5-4 mi/h) while accounting for subject age, weight, and gender. We solved linear regression equations for treadmill gait speed, expressed as a function of PA counts, age, weight, and gender. At all locations, cell phone PA counts were strongly associated with treadmill gait speed. Cell phones worn at the hip yielded the best predictive model. We conclude that in both men and women, cell phone derived activity counts strongly correlate with treadmill gait speed over a wide range of subject ages and weights.

Changes in objectively measured physical activity (performance) after epidural steroid injection for lumbar spinal stenosis

OBJECTIVE

To examine changes in objectively measured physical activity (performance) at 1 week following epidural steroid injection for lumbar spinal stenosis.

DESIGN

Prospective cohort.

SETTING

University spine program.

PARTICIPANTS

Individuals (N=17) who were undergoing fluoroscopically guided epidural steroid injection for symptomatic lumbar spinal stenosis (mean age ± SD, 70.1±6.7; 47% women).

INTERVENTION

Fluoroscopically guided epidural injection.

MAIN OUTCOME MEASURE(S)

The 2 primary outcomes, measured with accelerometers, were total activity (performance) measured over 7 days and maximum continuous activity (capacity). Walking capacity was also assessed with the Self-Paced Walking Test, and subjects completed the Oswestry Disability Index, Swiss Spinal Stenosis Questionnaire, Medical Outcomes Study 36-Item Short-Form Health Survey, visual analog pain scales, and body diagrams.

RESULTS

At 1 week postinjection, 58.8% of the subjects demonstrated increased total activity and 53% had increased maximum continuous activity, although neither change was statistically significant. Significant improvements were observed in a number of the self-report instruments, including the Physical Function Scale of the Swiss Spinal Stenosis Questionnaire, general health (Medical Outcomes Study 36-Item Short-Form Health Survey), role-limitation emotional (Medical Outcomes Study 36-Item Short-Form Health Survey), leg pain intensity (visual analog pain scales), and presence of leg weakness.

CONCLUSIONS

While patients perceived improvements in pain and function following injection, these improvements were not reflected in significant changes in performance or capacity. Future studies will continue to find value in subjective measures of pain and quality of life. However, with modern technology, performance is no longer a subjective variable. Use of activity monitors to objectively measure performance can result in more rigorous validation of treatment effects, while simultaneously highlighting the potential need for additional postinjection rehabilitation aimed at improving performance.

Social, environmental and psychological factors associated with objective physical activity levels in the over 65s

Objective

To assess physical activity levels objectively using accelerometers in community dwelling over 65 s and to examine associations with health, social, environmental and psychological factors.

Design

Cross sectional survey.

Setting

17 general practices in Scotland, United Kingdom.

Participants

Random sampling of over 65 s registered with the practices in four strata young-old (65–80 years), old-old (over 80 years), more affluent and less affluent groups.

Main Outcome Measures

Accelerometry counts of activity per day. Associations between activity and Theory of Planned Behaviour variables, the physical environment, health, wellbeing and demographic variables were examined with multiple regression analysis and multilevel modelling.

Results

547 older people (mean (SD) age 79(8) years, 54% female) were analysed representing 94% of those surveyed. Accelerometry counts were highest in the affluent younger group, followed by the deprived younger group, with lowest levels in the deprived over 80 s group. Multiple regression analysis showed that lower age, higher perceived behavioural control, the physical function subscale of SF-36, and having someone nearby to turn to were all independently associated with higher physical activity levels (R² = 0.32). In addition, hours of sunshine were independently significantly associated with greater physical activity in a multilevel model.

Conclusions

Other than age and hours of sunlight, the variables identified are modifiable, and provide a strong basis for the future development of novel multidimensional interventions aimed at increasing activity participation in later life.

Association of 1,25-dihydroxyvitamin D levels with physical performance and thigh muscle cross-sectional area in chronic kidney disease stage 3 and 4

BACKGROUND

Declines in 1,25-dihydroxyvitamin D (1,25(OH)₂D) levels and physical functioning follow the course of chronic kidney disease (CKD). Although the molecular actions of vitamin D in skeletal muscle are well known, and muscle weakness and atrophy are observed in vitamin D-deficient states, there is little information regarding vitamin D and muscle function and size in CKD.

OBJECTIVE

To examine associations of vitamin D with physical performance (PF) and muscle size.

DESIGN

Cross-sectional.

SETTING

CKD clinic.

SUBJECTS

Twenty-six patients (61 ± 13 years, 92% men) with CKD stage 3 or 4.

MAIN OUTCOME MEASURES

Gait speed, 6-minute walk, sit-to-stand time, 1-legged balance, and thigh muscle cross-sectional area (MCSA), measured by magnetic resonance imaging (MRI).

RESULTS

Overall, 73% were 25-hydroxyvitamin D (25(OH)D) deficient (n = 10) or insufficient (n = 9) (Kidney Disease Outcomes Quality Initiative guidelines). 25(OH)D level was associated with normal gait speed only (r = 0.41, P = .04). Normal and fast gait speed, the distance walked in 6 minutes, and sit-to-stand time were best explained by 1,25(OH)₂D and body mass index (P < .05 for all) and 1-legged stand by 1,25(OH)₂D (r = 0.40, P < .05) only. There were no associations of age, estimated glomerular filtration rate (eGFR), intact parathyroid hormone (iPTH), or albumin with any PF measures. MCSA was associated with eGFR (r = 0.54, P < .01) only. Variance in MCSA was best explained by a model containing 1,25(OH)₂D, plasma Ca²⁺, and daily physical activity (by accelerometry) (P < .05 for all). Once these variables were in the model, there was no contribution of eGFR.

CONCLUSION

These results suggest that 1,25(OH)₂D is a determinant of PF and muscle size in patients with stage 3 and 4 CKD.

Physical activity measured by the SenseWear Armband in women with rheumatoid arthritis

BACKGROUND

Individuals with rheumatoid arthritis (RA) often are sedentary and have an increased risk of developing comorbid conditions. Women with RA are more likely to experience challenges in maintaining an active lifestyle over their life span than men with RA or people who are healthy. As the benefits of physical activity (PA) are well known, measuring PA accurately in this population is important.

OBJECTIVES

The purposes of this study were: (1) to characterize PA as measured with the SenseWear Armband (SWA) in women with RA and (2) to determine the measurement time frame to obtain consistent estimates of PA and daily energy expenditure (EE) in women with RA.

DESIGN

This was a cross-sectional study.

METHODS

Participants wore the SWA for 7 days. Measurements of daily total energy expenditure (TEE), physical activity energy expenditure (PAEE) during activities at or above 1 metabolic equivalent (MET) level (PAEE≥1MET), PAEE during activities at or above 2 METs (PAEE≥2METs), PAEE during activities at or above 3 METs (PAEE≥3METs), and number of steps were obtained.

RESULTS

Fifty-three women participated. Complete data were obtained for 47 participants (89%). Daily usage of the SWA was 98% of the time (23:31 hours/24 hours). Means (SD) were 2,099 (340) kcal/d for TEE, 1,050 (331) kcal/d for PAEE≥1MET, 642 (309) kcal/d for PAEE≥2METs, 239 (178) kcal/d for PAEE≥3METs, and 7,260 (2,710) for number of steps. Results of intraclass correlation coefficient analyses and multiple linear regressions indicated that 2 days were needed to reliably estimate TEE; 3 days for PAEE≥1MET, PAEE≥2METs, and number of steps; and 4 days for PAEE≥3METs.

LIMITATIONS

The sample was composed of well-educated women with RA who had mild to moderate difficulty performing daily activities.

CONCLUSION

The SWA may be useful to quantify PA in women with RA and to monitor effectiveness of interventions aiming to increase PA levels. Minimizing the number of days necessary for data collection will reduce the individual's burden and may improve adherence in studies of PA behaviors.

Exercise intensity influences nonexercise activity thermogenesis in overweight and obese adults

PURPOSE

The purpose of this study was to determine the effect of acute bouts of moderate- and high-intensity walking exercise on nonexercise activity thermogenesis (NEAT) in overweight and obese adults.

METHODS

Sixteen participants performed a single bout of either moderate-intensity walking exercise (MIE) or high-intensity walking exercise (HIE) on two separate occasions. The MIE consisted of walking for 60 min on a motorized treadmill at 6 km·h(-1). The 60-min HIE session consisted of walking in 5-min intervals at 6 km·h(-1) and 10% grade followed by 5 min at 0% grade. NEAT was assessed by accelerometer 3 d before, on the day of, and 3 d after the exercise sessions.

RESULTS

There was no significant difference in NEAT vector magnitude (counts per minute) between the preexercise period (days 1-3) and the exercise day (day 4) for either the MIE or the HIE protocol. In addition, there was no change in NEAT during the 3 d after the MIE session; however, NEAT increased by 16% on day 7 (postexercise) compared with the exercise day (P = 0.32). However, during the postexercise period after the HIE session, NEAT was increased by 25% on day 7 compared with the exercise day (P = 0.08) and by 30%-33% compared with the preexercise period (days 1, 2, and 3; P = 0.03, 0.03, and 0.02, respectively).

CONCLUSION

A single bout of either MIE or HIE did not alter NEAT on the exercise day or on the first 2 d after the exercise session. However, monitoring NEAT on a third day allowed the detection of a 48-h delay in increased NEAT after performing HIE. A longer-term intervention is needed to determine the effect of accumulated exercise sessions over a week on NEAT.

Association of physical activity and prognostic parameters in elderly patients with heart failure

OBJECTIVE

Assessment of habitual physical activity (PA) in patients with heart failure.

METHODS

This study included 50 patients with heart failure (61.9 ± 4.0 yr). Seven days of PA were assessed by questionnaire (AQ), pedometer, and accelerometer and correlated with prognostic markers including VO(2peak), percent left-ventricular ejection fraction, N-terminal pro-B-type natriuretic peptide, and New York Heart Association (NYHA) functional class.

RESULTS

Accelerometry showed a stronger correlation with VO(2peak) and NYHA class (R = .73 and R = -.68; p < .001) than AQ (R = .58 and R = -.65; p < .001) or pedometer (R = .52 and R = -.50; p < .001). In the multivariable regression model accelerometry was the only consistent independent predictor of VO(2peak) (p = .002). Moreover, when its accuracy of prediction was tested, 59% of NYHA I and 95% of NYHA III patients were correctly classified into their assigned NYHA classes based on their accelerometer activity.

CONCLUSION

PA assessed by accelerometer is significantly associated with exercise capacity in patients with heart failure and is predictive of disease severity. The data suggests that PA monitoring can aid in evaluating clinical status.

Do pedometers increase physical activity in sedentary older women? A randomized controlled trial

OBJECTIVES

To determine the effectiveness of a behavior change intervention (BCI) with or without a pedometer in increasing physical activity in sedentary older women.

DESIGN

Prospective randomized controlled trial.

SETTING

Primary care, City of Dundee, Scotland.

PARTICIPANTS

Two hundred four sedentary women aged 70 and older.

INTERVENTIONS

Six months of BCI, BCI plus pedometer (pedometer plus), or usual care.

MEASUREMENTS

PRIMARY OUTCOME

change in daily activity counts measured by accelerometry.

SECONDARY OUTCOMES

Short Physical Performance Battery, health-related quality of life, depression and anxiety, falls, and National Health Service resource use.

RESULTS

One hundred seventy-nine of 204 (88%) women completed the 6-month trial. Withdrawals were highest from the BCI group (15/68) followed by the pedometer plus group (8/68) and then the control group (2/64). After adjustment for baseline differences, accelerometry counts increased significantly more in the BCI group at 3 months than in the control group (P = .002) and the pedometer plus group (P = .04). By 6 months, accelerometry counts in both intervention groups had fallen to levels that were no longer statistically significantly different from baseline. There were no significant changes in the secondary outcomes.

CONCLUSION

The BCI was effective in objectively increasing physical activity in sedentary older women. Provision of a pedometer yielded no additional benefit in physical activity, but may have motivated participants to remain in the trial.

Habitual physical activity levels are associated with performance in measures of physical function and mobility in older men

OBJECTIVES

To determine whether objectively measured physical activity levels are associated with physical function and mobility in older men.

DESIGN

Cross-sectional.

SETTING

Academic research center.

PARTICIPANTS

Eighty-two community-dwelling men aged 65 and older with self-reported mobility limitations were divided into a low-activity and a high-activity group based on the median average daily physical activity counts of the whole sample.

MEASUREMENTS

Physical activity according to triaxial accelerometers; physical function and mobility according to the Short Physical Performance Battery (SPPB), gait speed, stair climb time, and a lift-and-lower task; aerobic capacity according to maximum oxygen consumption (VO(2) max); and leg press and chest press maximal strength and peak power.

RESULTS

Older men with higher physical activity levels had a 1.4-point higher mean SPPB score and a 0.35-m/s faster walking speed than those with lower physical activity levels. They also climbed a standard flight of stairs 1.85 seconds faster and completed 60% more shelves in a lift-and-lower task (all P<.01); muscle strength and power measures were not significantly different between the low- and high-activity groups. Correlation analyses and multiple linear regression models showed that physical activity is positively associated with all physical function and mobility measures, leg press strength, and VO(2) max.

CONCLUSION

Older men with higher physical activity levels demonstrate better physical function and mobility than their less-active peers. Moreover, physical activity levels are predictive of performance in measures of physical function and mobility in older men. Future work is needed to determine whether modifications in physical activity levels can improve or preserve physical performance in later life.

Utility of the RT3 triaxial accelerometer in free living: an investigation of adherence and data loss

There is strong evidence for the protective effects of physical activity on chronic health problems. Activity monitors can objectively measure free living occupational and leisure time physical activity. Utility is an important consideration when determining the most appropriate monitor for specific populations and environments. Hours of activity data collected, the reasons for activity hours not being recorded, and how these two factors might change over time when using an activity monitor in free living are rarely reported. This study investigated user perceptions, adherence to minimal wear time and loss of data when using the RT3 activity monitor in 21 healthy adults, in a variety of occupations, over three (7 day) repeated weeks of measurement in free living. An activity diary verified each day of monitoring and a utility questionnaire explored participant perceptions on the usability of the RT3. The RT3 was worn for an average of 14 h daily with 90% of participants having complete data sets. In total 6535.8 and 6092.5h of activity data were collected from the activity diary and the RT3 respectively. An estimated 443.3h (6.7%) of activity data were not recorded by the RT3. Data loss was primarily due to battery malfunction (45.2%). Non-adherence to wear time accounted for 169.5h (38.2%) of data loss, of which 14 h were due to occupational factors. The RT3 demonstrates good utility for free living activity measurement, however, technical issues and strategies to manage participant adherence require consideration with longitudinal and repeated measures studies.

The Effects of Vitamin D Supplementation on Physical Function and Quality of Life in Older Patients With Heart Failure

Background— Low 25-hydroxyvitamin D levels, commonly found in older patients with heart failure, may contribute to the chronic inflammation and skeletal myopathy that lead to poor exercise tolerance. We tested whether vitamin D supplementation of patients with heart failure and vitamin D insufficiency can improve physical function and quality of life.

Methods and Results— In a randomized, parallel group, double-blind, placebo-controlled trial, patients with systolic heart failure aged ≥70 years with 25-hydroxyvitamin D levels <50 nmol/L (20 ng/mL) received 100 000 U of oral vitamin D2 or placebo at baseline and 10 weeks. Outcomes measured at baseline, 10 weeks, and 20 weeks were 6-minute walk distance, quality of life (Minnesota score), daily activity measured by accelerometry, Functional Limitations Profile, B-type natriuretic peptide, and tumor necrosis factor-α. Participants in the vitamin D group had an increase in their 25-hydroxyvitamin D levels compared with placebo at 10 weeks (22.9 versus 2.3 nmol/L [9.2 versus 0.9 ng/mL]; P <0.001) and maintained this increase at 20 weeks. The 6-minute walk did not improve in the treatment group relative to placebo. No significant benefit was seen on timed up and go testing, subjective measures of function, daily activity, or tumor necrosis factor. Quality of life worsened by a small, but significant amount in the treatment group relative to placebo. B-type natriuretic peptide decreased in the treatment group relative to placebo (−22 versus +78 pg/mL at 10 weeks; P =0.04).

Conclusions— Vitamin D supplementation did not improve functional capacity or quality of life in older patients with heart failure with vitamin D insufficiency.

Clinical Trial Registration— www.controlled-trials.com. Identifier: ISRCTN51372896.

Should oral nutritional supplementation be given to undernourished older people upon hospital discharge? A controlled trial

OBJECTIVES

To determine whether the oral nutritional supplementation of undernourished older people upon discharge from hospital improves muscle function and reduces disability.

DESIGN

Randomized controlled trial.

SETTING

Community-based study in two centers in Scotland.

PARTICIPANTS

Two hundred fifty-three people.

INTERVENTION

Randomization to oral nutritional supplementation (600 kcal/d) or control supplement of 200 kcal/d.

MEASUREMENTS

Primary outcome (20-point activity of daily living Barthel Index) and secondary outcomes (handgrip strength, Sit-to-Stand test, and Euroquol) were measured at baseline (after discharge from the hospital and before supplement was commenced) and 8 and 16 weeks and accelerometry-measured physical activity levels at baseline and 16 weeks. Falls were recorded prospectively.

RESULTS

Mean age was 82. There was no significant difference in change in Barthel score between supplement and control groups (adjusted mean difference=0.28, 95% confidence interval (CI)=-0.28-0.84). Handgrip strength improved more in the supplemented group (adjusted mean difference=1.52 kg, 95% CI=0.50-2.55; P=.004). The supplemented group exhibited modestly greater vector movement (overall activity) than controls (P=.02). There were no significant between-group differences in Sit-to-Stand test, health-related quality of life, or falls. Adherence was 38.2% in the nutritional supplement group and 50.0% in the control supplement group. Weight did not increase in the nutritional supplement group as a whole, but on-treatment analysis adjusting for adherence showed a mean weight gain of 1.17 kg (95% CI=0.07-2.27; P=.04) more than in controls.

CONCLUSION

Oral nutritional supplementation of undernourished older people upon hospital discharge did not reduce disability, despite improving handgrip strength and modestly increasing objectively measured physical activity levels. Lack of an effect of the nutritional supplement used in this study may have been due to low adherence, suggesting that different approaches to nutritional supplementation need to be tested in this population.

Seasonal changes in amount and patterns of physical activity in women

BACKGROUND

Environmental factors including seasonal changes are important to guide physical activity (PA) programs to achieve or sustain weight loss. The goal was to determine seasonal variability in the amount and patterns of free-living PA in women.

METHODS

PA was measured in 57 healthy women from metropolitan Nashville, TN, and surrounding counties (age: 20 to 54 years, body mass index: 17 to 48 kg/m2) using an accelerometer for 7 consecutive days during 3 seasons within 1 year. PA counts and energy expenditure (EE) were measured in a whole-room indirect calorimeter and used to model accelerometer output and to calculate daily EE and intensity of PA expressed as metabolic equivalents (METs).

RESULTS

PA was lower in winter than in summer (131+/-45 vs. 144+/-54x10(3) counts/d; P=.025) and in spring/fall (143+/-48x10(3) counts/d; P=.027). On weekends, PA was lower in winter than in summer by 22,652 counts/d (P=.008). In winter, women spent more time in sedentary activities than in summer (difference 35 min/d; P=.007) and less time in light activities (difference -29 min/d, P=.018) and moderate or vigorous activities (difference -6 min/d, P=.051).

CONCLUSIONS

Women living in the southeastern United States had lower PA levels in winter compared with summer and spring/fall, and the magnitude of this effect was greater on weekends than weekdays.

Wearable systems for monitoring mobility-related activities in older people: a systematic review

OBJECTIVE

The use of wearable motion-sensing technology offers important advantages over conventional methods for obtaining measures of physical activity and/or physical functioning in aged individuals. This review aims to identify the actual state of applying wearable systems for monitoring mobility-related activity in older populations. In this review we focus on technologies and applications, research designs, feasibility and adherence aspects, and clinical relevance of wearable motion-sensing technology.

DATA SOURCES

PubMed (MEDLINE since 1990), Ovid (BIOSIS, CINAHL), and Cochrane (Central) and reference lists of all relevant articles were searched.

REVIEW METHODS

Two authors independently reviewed randomized and non-randomized trials on people above 65 years systematically. Quality of selected articles was scored and study results were summarised and discussed.

RESULTS

Two hundred and twenty-seven abstracts were considered. After application of inclusion criteria and full text reading, 42 articles were taken into account in a full text review. Twenty of these papers evaluated walking with step counters, other papers used varying accelerometry approaches for obtaining overall activity measures (n = 16), or for monitoring changes in body postures and activity patterns (n = 17). Seven studies explicitly mentioned feasibility and/or adherence aspects. Eight studies presented outcome evaluations of interventions. Eight articles were representing descriptive research designs, three articles were using mixed descriptive and exploratory research designs, 23 articles used exploratory research-type designs, and eight articles used experimental research designs.

CONCLUSION

Although feasible methods for monitoring human mobility are available, evidence-based clinical applications of these methods in older populations are in need of further development.