Long-period accelerometer monitoring shows the role of physical activity in overweight and obesity

A biopsychosocial approach towards understanding disparities in exercise participation between Hispanic and non-Hispanic White patients living with knee osteoarthritis

Engaging in regular exercise is essential for managing knee osteoarthritis (KOA) symptoms. Despite the established findings, sustained exercise adoption remains a challenge for KOA patients, with notable disparities among Hispanic patients, warranting a need to identify determinants that explain the racial discrepancy in exercise participation. The purpose of this study was to employ a biopsychosocial model to identify determinants of exercise participation and highlight racial disparities. Patients (n = 163) from a university hospital clinic were medically examined to be considered eligible for the study based on radiographs. Eligible participants completed validated survey measures that assessed exercise participation over the past two weeks, along with measures from biological, psychological and social domains to predict future intention exercise. Structural equation modelling tested hypothesized the paths. Past exercise behavior predicted attitudes, self-efficacy, and future exercise intentions. Pain catastrophizing correlated with exercise participation, but the competing effects of physician and (personal) social support on exercise nullified the significance of pain catastrophizing to exercise participation. Significant ethnicity comparisons found non-Hispanic white patients to have higher education, income, lower BMI, stronger scores on attitudes and self-efficacy, and greater exercise participation time. Non-significant effects between the two ethnicities include intention, physician support, and social support. Designing an intervention that helps foster support from the patient's physician and proximal friends/family members can play a vital role in exercise participation for both ethnicities. Additional focus on developing attitudes and self-efficacy among Hispanics can address some disparities. Further notes on promoting exercise equity using a biopsychosocial approach are provided.

Association between physical activity and the N-terminal pro-brain natriuretic peptide in a middle-aged Japanese population: The interaction with alcohol consumption, 2005-2006

OBJECTIVE

Higher N-terminal pro-brain natriuretic peptide (NT-proBNP) levels are a strong risk factor for cardiovascular disease. The current study aimed to clarify the cross-sectional association of physical activity (PA) with NT-proBNP and to identify the interaction of PA with alcohol consumption or cigarette smoking in middle-aged individuals.

METHODS

The study included 4613 individuals (1824 men and 2789 women) (November 2005-November 2006). Total PA, steps, light-intensity PA (LPA), and moderate-to-vigorous-intensity PA (MVPA) were assessed using accelerometer. Serum NT-proBNP levels were measured. Cross-sectional associations of total PA and steps with NT-proBNP were analyzed using multiple regression with adjustment for potential confounders. The isotemporal substitution model was used to assess activity intensity-specific association. The interaction between PA and alcohol consumption or smoking was also examined.

RESULTS

Total PA was independently and inversely associated with NT-proBNP in the entire sample (P = 0.04). The inverse association of substituting LPA with MVPA for NT-proBNP was clearer in men than in women (Pinteraction = 0.04). Inverse associations of total PA or steps with NT-proBNP were clearer in heavy drinkers than in moderate drinkers and non-drinkers in the entire sample (Pinteraction < 0.05). In men, the inverse association of substituting LPA with MVPA for NT-proBNP was also clearer in heavy drinkers (Pinteraction = 0.02). No interactions of PA with smoking were detected.

CONCLUSIONS

Higher total PA was associated with better NT-proBNP in middle-aged individuals. Additionally, the effect of substituting LPA with MVPA on NT-proBNP was greater in men than in women. Furthermore, the association between PA and NT-proBNP may be modified by alcohol consumption.

Data Analytics in Physical Activity Studies With Accelerometers: Scoping Review

BACKGROUND

Monitoring free-living physical activity (PA) through wearable devices enables the real-time assessment of activity features associated with health outcomes and provision of treatment recommendations and adjustments. The conclusions of studies on PA and health depend crucially on reliable statistical analyses of digital data. Data analytics, however, are challenging due to the various metrics adopted for measuring PA, different aims of studies, and complex temporal variations within variables. The application, interpretation, and appropriateness of these analytical tools have yet to be summarized.

OBJECTIVE

This research aimed to review studies that used analytical methods for analyzing PA monitored by accelerometers. Specifically, this review addressed three questions: (1) What metrics are used to describe an individual's free-living daily PA? (2) What are the current analytical tools for analyzing PA data, particularly under the aims of classification, association with health outcomes, and prediction of health events? and (3) What challenges exist in the analyses, and what recommendations for future research are suggested regarding the use of statistical methods in various research tasks?

METHODS

This scoping review was conducted following an existing framework to map research studies by exploring the information about PA. Three databases, PubMed, IEEE Xplore, and the ACM Digital Library, were searched in February 2024 to identify related publications. Eligible articles were classification, association, or prediction studies involving human PA monitored through wearable accelerometers.

RESULTS

After screening 1312 articles, 428 (32.62%) eligible studies were identified and categorized into at least 1 of the following 3 thematic categories: classification (75/428, 17.5%), association (342/428, 79.9%), and prediction (32/428, 7.5%). Most articles (414/428, 96.7%) derived PA variables from 3D acceleration, rather than 1D acceleration. All eligible articles (428/428, 100%) considered PA metrics represented in the time domain, while a small fraction (16/428, 3.7%) also considered PA metrics in the frequency domain. The number of studies evaluating the influence of PA on health conditions has increased greatly. Among the studies in our review, regression-type models were the most prevalent (373/428, 87.1%). The machine learning approach for classification research is also gaining popularity (32/75, 43%). In addition to summary statistics of PA, several recent studies used tools to incorporate PA trajectories and account for temporal patterns, including longitudinal data analysis with repeated PA measurements and functional data analysis with PA as a continuum for time-varying association (68/428, 15.9%).

CONCLUSIONS

Summary metrics can quickly provide descriptions of the strength, frequency, and duration of individuals' overall PA. When the distribution and profile of PA need to be evaluated or detected, considering PA metrics as longitudinal or functional data can provide detailed information and improve the understanding of the role PA plays in health. Depending on the research goal, appropriate analytical tools can ensure the reliability of the scientific findings.

Historical development of accelerometry measures and methods for physical activity and sedentary behavior research worldwide: A scoping review of observational studies of adults

This scoping review identified observational studies of adults that utilized accelerometry to assess physical activity and sedentary behavior. Key elements on accelerometry data collection were abstracted to describe current practices and completeness of reporting. We searched three databases (PubMed, Web of Science, and SPORTDiscus) on June 1, 2021 for articles published up to that date. We included studies of non-institutionalized adults with an analytic sample size of at least 500. The search returned 5686 unique records. After reviewing 1027 full-text publications, we identified and abstracted accelerometry characteristics on 155 unique observational studies (154 cross-sectional/cohort studies and 1 case control study). The countries with the highest number of studies included the United States, the United Kingdom, and Japan. Fewer studies were identified from the continent of Africa. Five of these studies were distributed donor studies, where participants connected their devices to an application and voluntarily shared data with researchers. Data collection occurred between 1999 to 2019. Most studies used one accelerometer (94.2%), but 8 studies (5.2%) used 2 accelerometers and 1 study (0.6%) used 4 accelerometers. Accelerometers were more commonly worn on the hip (48.4%) as compared to the wrist (22.3%), thigh (5.4%), other locations (14.9%), or not reported (9.0%). Overall, 12.7% of the accelerometers collected raw accelerations and 44.6% were worn for 24 hours/day throughout the collection period. The review identified 155 observational studies of adults that collected accelerometry, utilizing a wide range of accelerometer data processing methods. Researchers inconsistently reported key aspects of the process from collection to analysis, which needs addressing to support accurate comparisons across studies.

Pruning Growing Self-Organizing Map Network for Human Physical Activity Identification

Human physical activity identification based on wearable sensors is of great significance to human health analysis. A large number of machine learning models have been applied to human physical activity identification and achieved remarkable results. However, most human physical activity identification models can only be trained based on labeled data, and it is difficult to obtain enough labeled data, which leads to weak generalization ability of the model. A Pruning Growing SOM model is proposed in this paper to address the limitations of small-scale labeled dataset, which is unsupervised in the training stage, and then only a small amount of labeled data is used for labeling neurons to reduce dependency on labeled data. In training stage, the inactive neurons in network can be deleted by pruning mechanism, which makes the model more consistent with the data distribution and improves the identification accuracy even on unbalanced dataset, especially for the action categories with poor identification effect. In addition, the pruning mechanism can also speed up the inference of the model by controlling its scale.

Assessing changes in mood state in university students following short-term study abroad

Short-term study-abroad (STSA) programs provide a more accessible alternative for students who would otherwise not consider engaging in academic activities overseas. Though improvements in the levels of intercultural sensitivity and general academic aspects attained by STSA programs have been previously examined, much less is known regarding the impact such programs have in the mood of students. Here, we examined changes in mood state associated with participation in an STSA program in a group of Japanese university students. Mood states were assessed using the Profile of Mood States (POMS), the Satisfaction With Life Scale (SWLS), and the Gratitude Questionnaire (GQ-6). Results indicated that the POMS mean scores of Vigor-Activity and SWLS peaked at the time immediately following participation in the STSA program; moreover, the same scores were found to be at comparable levels even one month after the end of the program. These results indicate that participation in STSA programs can positively influence the mood state of university students, suggesting that the benefits associated with participation in such programs extend beyond typically reported improvements in the academic domain.

Effects of Substituting Sedentary Behavior with Light-Intensity or Moderate-to-Vigorous Physical Activity on Obesity Indices in Adults: A Prospective Short-Term Follow-Up Study

BACKGROUND

Sedentary behavior (SB) is an independent risk factor for cardiovascular diseases. We hypothesized that there may be benefits of replacing SB with light-intensity (LIPA) and moderate-to-vigorous (MVPA) physical activity. Substituting SB with LIPA and MVPA might be associated with body composition changes.

METHODS

We assessed body weight, body mass index (BMI), fat body mass (FBM), and physical activity level, as well as one-year changes, in 780 adults (EPIMOV Study).

RESULTS

We analyzed into 10-min blocks SB, LIPA, MVPA, and total wear time. After 14 ± 3 months of follow-up, there were 242 completed procedures. We reallocated time spent in SB to LIPA or MVPA and assessed cross-sectional and prospective associations with the outcomes using isotemporal substitution models. In cross-sectional analysis, substituting 10-min blocks of SB with MVPA led to significant decreases of 1.23 kg in body weight, 0.30 kg/m² in BMI, and 0.38% in FBM. 10-min blocks substituting SB with LIPA produced significantly lower body weight (1 kg) and BMI (0.1 kg/m²) values. In longitudinal analysis, reallocating SB to MVPA was only associated with FBM decline (-0.31%).

CONCLUSIONS

Substituting SB with MVPA is associated with significant improvement in obesity indices in both cross-sectional and follow-up. Replacing SB with LIPA produced a less consistent impact.

Sedentary time, physical activity, and serum SPARC in a middle-aged population

The influence of habitual physical activity (PA) on the circulating levels of secreted protein acidic and rich in cysteine (SPARC) remains unclear. The purpose of the current study was to clarify the effects of sedentary time, light-intensity PA (LPA), and moderate- to vigorous-intensity PA (MVPA) on the serum SPARC in a general middle-aged population. The current study is a cross-sectional study of 4,000 men and 6,040 women (40-69 years). Sedentary time, LPA, and MVPA were objectively measured by an accelerometer. The serum SPARC concentration was measured by enzyme-linked immunosorbent assay. Using an isotemporal substitution model, cross-sectional associations of replacing sedentary time with either LPA or MVPA on serum SPARC levels were analysed according to sex. Interactions with subject characteristics, such as the body mass index (BMI), smoking, and alcohol consumption, were also examined. In men, replacing 60 min of sedentary time with 60 min of MVPA was significantly associated with 23 ng/mL lower serum SPARC levels (confidence interval: -43, -2) after adjusting for confounders, including the BMI (P = 0.028). A significant interaction between replacing sedentary behaviour with LPA and the BMI on SPARC was detected in women (P = 0.029), although the stratified associations for each BMI level (<25 or ≥25 kg/m²) did not reach significance. The current study suggests that replacing sedentary time with MVPA is associated with reduced serum SPARC levels in middle-aged men, but not in women. In addition, a potential interaction between LPA and the BMI on SPARC was also found in women.

Association between obesity and sedentary behavior in adults

Abstract Although sedentary behavior (SB) is related to the development of metabolic diseases, there is still no consensus in literature about the association between accelerometer-based SB and obesity, especially adjusted for cardiovascular risk factors and level of daily physical activities. The aim was to evaluate the association between obesity and SB adjusted for potential confounders in adults. Data from 780 participants of the Epidemiology and Human Movement (EPIMOV) Study were analyzed. Body weight, body mass index (BMI), and fat body mass as percentage (%FBM) (bioelectrical impedance) were obtained and, then, used to stratify participants. SB was objectively measured using triaxial waist-worn accelerometers placed above the dominant hip during waking hours for at least four consecutive days (4-7 days). SB and its pattern were not significantly different between obesity groups. Although SB presented some significant correlations with obesity, the correlation and determination coefficient indicated weak association between SB and obesity (e.g., BMI and %FBM). Obesity presented little or no association with SB and its pattern after adjustment for potential confounders, especially when SB is measured through accelerometry.

Myokines: a descriptive review

In the last years, scientists have shown that skeletal muscle is not a pure locomotor unit or responsible for propulsion and posture. Skeletal muscle encompasses one of the major organs of the body (constituting about 40% of the body mass in non-obese men). It regulates energy and metabolic processes and is now recognized as an organ capable of producing molecules with vital functions. These molecules are termed myokines, a new field of research in the health sciences, and represent an open field of discoveries and applications in several areas. The aim of this review was to show the role of some well-known myokines in the maintenance of homeostasis. Our search was performed in databases such as Medline/Pubmed, Embase and Scielo. Some relevant myokines are interleukin-6 (IL-6), IL-8, IL-15, irisin, myostatin, fibroblast growth factor 21 (FGF21), leukemia inhibitory factor (LIF), brain-derived neurotrophic factor (BDNF), and insulin-like growth factor-1 (IGF-1). They are related to play a positive or negative role in muscle function and metabolism homeostasis. They are associated with the regulation of glucose and lipid metabolism, the deposition of fat in the adipose tissue, and the "browning" of the white adipose tissue. For these reasons, they can interfere with the prevention of obesity, diabetes, metabolic syndrome, and cardiovascular diseases. The discovery of the myokines has opened a new direction in understanding the effects of exercises on humans.

Effect of handling breaks on estimation of heart rate responses to bouts of physical activity among young women: An accelerometer research issue

BACKGROUND

One of the research interests with regard to accelerometry is the evaluation of physical activity bout under free-living conditions.

RESEARCH QUESTION

This study aimed to examine the effect of treatment interruption on the estimation of heart rate (HR) response to moderate-to-vigorous intensity physical activity (MVPA) bout.

METHODS

Twenty-five young women performed at least 30 min of MVPA during 24 h while wearing a uniaxial accelerometer on their waist and a portable HR monitor on their chest simultaneously. Based on the time series data, MVPA bout was defined as physical activity that was maintained at no less than 3 metabolic equivalents (METs) for >10 min without or with interruption, i.e., a 1-, 2-, or 3-min interruption.

RESULTS

The frequency and duration of MVPA bout significantly increased with interruption (p < 0.01). The HR and estimated MET value for an MVPA bout with interruption were significantly lower than those without interruption (p < 0.01), and the difference gradually increased depending on the duration of the interruptions (p < 0.01).

SIGNIFICANCE

These findings indicate that treatment interruptions could influence the estimation of cardiorespiratory response to MVPA bout under free-living conditions, and interruptions could result in an overestimation of the actual intensity of an MVPA bout.

The interaction between FTO rs9939609 and physical activity is associated with a 2-fold reduction in the risk of obesity in Korean population

OBJECTIVE

FTO (fat mass and obesity-associated) gene is a well-known genetic risk factor for obesity. We investigated whether physical activity modulates the effect of FTO rs9939609 on obesity in Korean population.

METHODS

The study analyzed the correlation between physical activity and obesity in 8840 individuals representing the Korea Association Resource (KARE). The association between obesity-related traits and single-nucleotide polymorphisms (SNPs) was assessed using linear regression models. Physical activity was defined as 3 hours or more of daily intense activity.

RESULTS

Participants carrying rs9939609 (AT+AA) genotypes showed higher BMI compared with those carrying the wild-type (TT) homozygote. The highest significant association was observed between obesity-related traits (ß = .334, P value = 1.76 × 10^-6 ). FTO rs9939609 (AT+AA) increased the risk of obesity (OR = 1.42, CI [1.13-1.79]), which was correlated with BMI correlations. However, active exercise by subjects carrying the same genotype reduced the risk of obesity by nearly 2-fold (OR = 0.62, CI [0.25-0.84]). In contrast, TT genotype was not statistically significant in reducing the risk of obesity in the active exercise group.

CONCLUSIONS

Our results support a previous finding correlating FTO and obesity-related traits and suggest that the interaction with genetic variation and physical activity is an important risk factor for obesity.

Intensity-Specific and Modified Effects of Physical Activity on Serum Adiponectin in a Middle-Aged Population

Context

The effects of intensity-specific physical activity (PA) and its interaction with other lifestyle factors on serum adiponectin are currently unclear.

Objective

To investigate the effects of replacing sedentary time with either light-intensity PA (LPA) or moderate- to vigorous-intensity PA (MVPA) on total and high-molecular-weight (HMW) adiponectin and to examine interactions with smoking, alcohol drinking, coffee consumption, and menopausal status in a general population.

Design/Setting

Cross-sectional study of 4013 men and 6050 women (40 to 69 years of age).

Main Outcome Measures

The associations of replacing sedentary time with LPA or MVPA on total and HMW adiponectin were analyzed using an isotemporal substitution model.

Results

In men, reallocating 60 minutes of sedentary time to 60 minutes of LPA was associated with 9% and 13% higher total and HMW adiponectin levels even after adjusting for confounders, although such associations were not observed for MVPA. A similar pattern of results was also seen in women. The effect of replacing sedentary time with LPA on adiponectin was clearer in middle/high coffee consumers than in low coffee consumers among women. Although increasing the effect of replacing sedentary time with MVPA on adiponectin was clearer in former/current smokers than in never smokers among men, the replacement effect for MVPA on total adiponectin was clearer in premenopausal women than in postmenopausal women.

Conclusions

Replacing sedentary time with LPA resulted in increased levels of total and HMW adiponectin. The replacement effects for LPA or MVPA were found to be multiply modified by smoking, coffee consumption, and menopausal status.

The Introduction of an Active Rest Program by Workplace Units Improved the Workplace Vigor and Presenteeism Among Workers: A Randomized Controlled Trial

OBJECTIVE

The present study was designed to examine the effects of active rest by workplace units on not only workers' individual vigor but also workplace vigor and presenteeism.

METHODS

A total of 130 workers performed our active rest (short-time exercise) program for 10 minutes per day during their lunch breaks, three to four times per week for 8 weeks. Subjects from a workplace unit were randomly allocated to the intervention (n = 66) or control (n = 64) groups. The participants' work engagement and Work Functioning Impairment Scale (WFun) were examined at the baseline and after the 8-week intervention period.

RESULTS

After 8 weeks, the intervention group showed improved "vigor" values in work engagement and WFun (P < 0.05).

CONCLUSION

These results suggest that the introduction of active rest program by workplace units provides a viable means for improving workplace vigor and presenteeism.

Obesity History and Daily Patterns of Physical Activity at Age 60-64 Years: Findings From the MRC National Survey of Health and Development

Background

The aim of this study was to investigate associations of current body mass index (BMI) and obesity history with daily patterns of physical activity.

Methods

At age 60-64, participants from a British birth cohort study wore accelerometers for 5 days. Accelerometry counts were log-transformed and mean log-counts were used to derive a summary variable indicating total daily log-activity counts. Among those with complete data (n = 1,388) the associations of current BMI and age of first obesity were examined with: (a) total daily log-activity counts and (b) total log-activity counts in four segments of the day.

Results

Higher current BMI and younger age at obesity were strongly associated with lower levels of total daily activity at age 60-64 even after adjustment for sex, socioeconomic factors, and health status. The fully-adjusted mean difference in total daily log-activity counts was -581.7 (95% confidence interval: -757.2, -406.3) when comparing BMI ≥35 kg/m2 with <25 kg/m2, representing an 18.4% difference. Participants who had been obese since early adulthood had the lowest levels of activity (mean difference in total daily log-activity counts was -413.1 (-638.1, -188.2) when comparing those who were obese by age 26 or 36 with those who were never obese, representing a 13.1% difference).

Conclusions

Obese older adults may require targeted interventions and additional support to improve their daily activity levels. As younger generations with greater lifetime exposure to obesity reach old age the proportion of adults achieving sufficient levels of activity to realize its associated health benefits is likely to decline.

Factors Associated With Ambulatory Activity in De Novo Parkinson Disease

BACKGROUND AND PURPOSE

Objective ambulatory activity during daily living has not been characterized for people with Parkinson disease prior to initiation of dopaminergic medication. Our goal was to characterize ambulatory activity based on average daily step count and examine determinants of step count in nonexercising people with de novo Parkinson disease.

METHODS

We analyzed baseline data from a randomized controlled trial, which excluded people performing regular endurance exercise. Of 128 eligible participants (mean ± SD = 64.3 ± 8.6 years), 113 had complete accelerometer data, which were used to determine daily step count. Multiple linear regression was used to identify factors associated with average daily step count over 10 days. Candidate explanatory variable categories were (1) demographics/anthropometrics, (2) Parkinson disease characteristics, (3) motor symptom severity, (4) nonmotor and behavioral characteristics, (5) comorbidities, and (6) cardiorespiratory fitness.

RESULTS

Average daily step count was 5362 ± 2890 steps per day. Five factors explained 24% of daily step count variability, with higher step count associated with higher cardiorespiratory fitness (10%), no fear/worry of falling (5%), lower motor severity examination score (4%), more recent time since Parkinson disease diagnosis (3%), and the presence of a cardiovascular condition (2%).

DISCUSSION AND CONCLUSIONS

Daily step count in nonexercising people recruited for this intervention trial with de novo Parkinson disease approached sedentary lifestyle levels. Further study is warranted for elucidating factors explaining ambulatory activity, particularly cardiorespiratory fitness, and fear/worry of falling. Clinicians should consider the costs and benefits of exercise and activity behavior interventions immediately after diagnosis of Parkinson disease to attenuate the health consequences of low daily step count.Video Abstract available for more insights from the authors (see Video, Supplemental Digital Content 1, http://links.lww.com/JNPT/A170).

Mammographic Density and Vitamin D Levels - A Cross-sectional Study

Background Some studies have already proposed an inverse association between vitamin D levels and breast density. As breast density is already considered an established risk factor for breast cancer, such a connection could offer a new starting point for the prevention of breast cancer. Material and Methods To investigate this suggested connection, a total of 412 pre- and 572 post-menopausal women for whom mammography was indicated were recruited into this cross-sectional study. In addition to a questionnaire-based interview on the patient's general and gynecological medical history, her eating habits and lifestyle, serum levels of 25-hydroxyvitamin D [25(OH)D], calcium, phosphate and creatinine were determined. Breast density was determined by mammography and categorized as 1 to 4 according to the ACR classification. In addition to performing descriptive analysis to get a better overview of the data, a number of multivariate regression models were developed to determine the impact of confounders and the connection between vitamin D and mammographic density. Results More than half of all participants had low levels of 25(OH)D (< 20 ng/ml) and only a small minority of women (5.7 %) had what are currently considered to be optimal serum levels of 25(OH)D of at least 30 ng/ml. The significant majority of the cohort had a medium mammographic density (n = 463 had ACR 2; n = 343 had ACR 3). Logistic regression analysis showed that lower 25(OH)D serum levels were associated significantly more often with high rather than medium breast density. This association remained, even after adjusting for other factors which influence breast density such as age, BMI and menopausal status (p = 0.032 for ACR 4 vs. ACR 2; p = 0.028 for ACR 4 vs. ACR 3). When the same analysis was done separately for pre-menopausal and post-menopausal women, BMI in both groups was found to be inversely correlated with breast density and this inverse correlation was highly significant. In post-menopausal women, age was found to be similarly correlated while 25(OH)D did not appear to be associated with ACR. In pre-menopausal women the opposite was the case: although there was no correlation between age and breast density, higher vitamin D levels tended to be associated with lower breast density (p = 0.06 for ACR 2 vs. ACR 4) in this smaller sample (n = 412). When vitamin D-rich food and food supplements were also taken into account, regular intake of vitamin D preparations was associated with lower breast density; this association achieved borderline statistical significance (p = 0.05 for ACR 3 vs. ACR 4). When the analysis also took menopausal status into account, the breast density of pre-menopausal women was lower following regular vitamin D intake and this lower breast density of pre-menopausal women was statistically highly significant (p < 0.001 for ACR 1 and ACR 2 vs. ACR 4, respectively). This effect was not found in post-menopausal women. Frequent intake of vitamin D-containing nutrition had no significant impact on ACR in either of the groups. Conclusion These results reinforce the assumption previously proposed by several authors that higher levels of 25(OH)D pre-menopause and vitamin D substitution are associated with lower breast density and could reduce the risk of breast cancer. The findings did not confirm any post-menopausal association between vitamin D and mammographic breast density.

The practice of active rest by workplace units improves personal relationships, mental health, and physical activity among workers

Aim:

This study was designed to clarify the effects of active rest, with a focus on the practice of short-time group exercise by workplace units, on personal relationships, mental health, physical activity, and work ability among workers.

Methods:

Fifty-nine white-collar workers (40 males and 19 females) performed our active rest (short-time exercise) program, which consists of warm-up, cognitive functional training, aerobic exercise, resistance training and cool-down for 10 minutes per day, 3 times per week during their lunch breaks for 10 weeks. Participants from a workplace unit were randomly allocated to the intervention (five workplaces, n=29) or control groups (six workplaces, n=30). The participants' anthropometric measurements, and their Profile of Mood States (POMS) 2, Brief Job Stress Questionnaire (BJSQ), physical activity levels and Work Ability Index were examined at the baseline and after the 10-week intervention.

Results:

After 10 weeks, physical activity levels, especially the time spent in moderate and vigorous intensity, increased in the intervention group (p<0.05). The items of "vigor-activity" and "friendliness" improved in POMS 2, while "vigor," "interpersonal stress," "support from superiors, colleagues, and family/friends," and "job satisfaction" improved in BJSQ in the intervention group (p<0.05). In the intervention group, the number of exercise participation was positively correlated with the change in "vigor-activity" in POMS 2 (r=0.467, p=0.011).

Conclusions:

These results suggest that the practice of active rest by workplace units is important for improving personal relationships, mental health, and physical activity among workers.

Assessing the Causality Factors in the Association between (Abdominal) Obesity and Physical Activity among the Newfoundland Population-A Mendelian Randomization Analysis

A total of 1,263 adults from Newfoundland and Labrador were studied in the research. Body mass index (BMI) and percent trunk fat (PTF) were analyzed as biomarkers for obesity. The Mendelian randomization (MR) approach with two single-nucleotide polymorphisms in the fat-mass and obesity (FTO) gene as instruments was employed to assess the causal effect. In both genders, increasing physical activity significantly reduced BMI and PTF when adjusted for age and the FTO gene. The effect of physical activity was stronger on PTF than BMI. Direct observational analyses showed significant increase in BMI/PTF when physical activity decreased. A similar association in MR analyses was not significant. The association between physical activity and BMI/PTF could be due to reversed causality or common confounding factors. Our study provides insights into the causal contributions of obesity to physical activity in adults. Health intervention strategies to increase physical activity among adults should include some other plans such as improving diet for reducing obesity.

Utilization and Harmonization of Adult Accelerometry Data: Review and Expert Consensus

PURPOSE

This study aimed to describe the scope of accelerometry data collected internationally in adults and to obtain a consensus from measurement experts regarding the optimal strategies to harmonize international accelerometry data.

METHODS

In March 2014, a comprehensive review was undertaken to identify studies that collected accelerometry data in adults (sample size, n ≥ 400). In addition, 20 physical activity experts were invited to participate in a two-phase Delphi process to obtain consensus on the following: unique research opportunities available with such data, additional data required to address these opportunities, strategies for enabling comparisons between studies/countries, requirements for implementing/progressing such strategies, and value of a global repository of accelerometry data.

RESULTS

The review identified accelerometry data from more than 275,000 adults from 76 studies across 36 countries. Consensus was achieved after two rounds of the Delphi process; 18 experts participated in one or both rounds. The key opportunities highlighted were the ability for cross-country/cross-population comparisons and the analytic options available with the larger heterogeneity and greater statistical power. Basic sociodemographic and anthropometric data were considered a prerequisite for this. Disclosure of monitor specifications and protocols for data collection and processing were deemed essential to enable comparison and data harmonization. There was strong consensus that standardization of data collection, processing, and analytical procedures was needed. To implement these strategies, communication and consensus among researchers, development of an online infrastructure, and methodological comparison work were required. There was consensus that a global accelerometry data repository would be beneficial and worthwhile.

CONCLUSIONS

This foundational resource can lead to implementation of key priority areas and identification of future directions in physical activity epidemiology, population monitoring, and burden of disease estimates.

Physical activity and dietary intake in BMI discordant identical twins

OBJECTIVE

Despite the latest discovery of obesity-associated genes, the rapid rise in global obesity suggests a major role for environmental factors. This study investigated the influence of environmental factors on physical activity and dietary intake independent of genetic effects.

METHODS

Sixteen female monozygotic twins aged 48.8 ± 9.8 years (range 37-70) with a mean BMI discordance of 3.96 ± 2.1 kg/m(2) (range 0.7-8.2) were studied. Physical activity was determined using 7-day accelerometry and dietary intake using 3-day 24-h recalls.

RESULTS

Heavier cotwins were generally less physically active (mean activity counts × 1,000 per day ± SD; 505.5 ± 155.1 vs. 579.6 ± 185.4, P = 0.047) and tended to spend 6.1 min/day less in moderate to vigorous physical activity than leaner cotwins (P = 0.09). Energy intake did not significantly differ within pairs. Total fat intake (en%; P = 0.03), specifically monounsaturated fat (P < 0.01) and polyunsaturated fat (P = 0.08), was higher in the heavier cotwins.

CONCLUSIONS

After eliminating genetic effects, higher BMI is associated with lower overall and moderate to vigorous physical activity and higher intake of total fat, although the direction of causality cannot be determined. Future identification of the environmental factors responsible for these findings might contribute to developing new strategies in managing obesity.

The Association of Physical Activity during Weekdays and Weekend with Body Composition in Young Adults

Physical activity (PA) is a key contributor in long-term weight management but there remains limited research on the association between weekly PA patterns and weight change. The purpose of the present study was to examine the prospective association between weekly PA patterns and weight change in generally healthy young adults. Anthropometric measurements, including dual X-ray absorptiometry, were obtained every 3 months over a period of one year in 338 adults (53% male). At each measurement time, participants wore a multisensor device for a minimum of 10 days to determine total daily energy expenditure and time spent sleeping, sedentary, in light PA (LPA), in moderate PA (MPA), and in vigorous PA (VPA). PA did not differ between weekdays and the weekend at baseline. Twenty-four-hour sleep time, however, was significantly longer during weekends compared to weekdays, which was associated with less time spent sedentary. Weight loss was associated with a significant increase in LPA at the expense of sedentary time during the weekend but not during weekdays. Regression analyses further revealed an inverse association between change in VPA during the weekend and body composition at 12-month follow-up. Taken together, these results suggest that weekend PA plays an important role in long-term weight management.

Differences in correlates of energy balance in normal weight, overweight and obese adults

PURPOSE

The purpose of this study was to examine differences in total daily energy expenditure (TDEE), energy expenditure in various intensities, as well as total daily energy intake (TDEI) and diet quality in normal weight, overweight and obese men and women. Further, the association of energy expenditure and energy intake with body fatness was examined.

METHODS

The cross-sectional analysis included 430 adults (27.7 ± 3.8 years; 49.3% male). Body weight and height were measured according to standard procedures and percent body fat (BF) was assessed via dual X-ray absorptiometry. Energy expenditure was determined via the SenseWear Armband. Energy intake and the Healthy Eating Index (HEI) were calculated based on multiple 24-h recalls.

RESULTS

Weight adjusted TDEI and TDEE were significantly lower in overweight and obese adults compared to their normal weight peers (p < 0.001) and obese women had a lower HEI (p = 0.006). Overweight and obese adults further displayed a higher proportion of energy expenditure spent in sedentary and in light activities (p < 0.001), while the proportion of energy expenditure in moderate-to-vigorous physical activity (MVPA) was lower compared to their normal weight peers (p < 0.001). The inverse relationship between BMI or BF and MVPA was stronger than the positive association between BMI or BF and the proportion of energy expended in sedentary or light pursuits (r MPA = -0.45 to -0.67/r MVPA = -0.51 to -0.66 vs. r Sedentary = 0.33 to 0.52/r light = 0.36 to 0.47; p < 0.001).

CONCLUSIONS

These findings emphasise the importance of MPA and bouts of MVPA regarding the maintenance of a normal body weight.

Assessing Walking Activity in Older Adults: Development and Validation of a Novel Computer-Animated Assessment Tool

BACKGROUND

Assessing volume of physical activity (PA) in older adults is critical to understanding the role that PA has on health outcomes and the effectiveness of treatment interventions to increase PA. The purpose of this study was to investigate the psychometric properties of a novel computer-animated self-report questionnaire designed to assess walking activity of older adults: the Mobility Assessment Tool for Walking--the MAT-W.

METHODS

We recruited 249 older adults (66.9±4.7 years, 71% female, 32% black) with cardiovascular disease and/or metabolic syndrome as part of the Cooperative Lifestyle Intervention Program-II study. Participants completed the MAT-W at baseline and after 6 months of a walking and weight loss (n = 78) or weight loss only (n = 69) intervention. Test-retest reliability was assessed in 31 participants. Walking speed at usual and fast pace was measured using a GAITRite mat, and 7-day accelerometry data were collected at baseline and 6 months. The mCHAMPS5, a modified version of a widely used self-report PA questionnaire, was completed at baseline.

RESULTS

The test-retest reliability of MAT-W was excellent (intraclass correlation coefficient > .85). The MAT-W was correlated with mCHAMPS5 (Spearman r = .66, p < .001) and moderate/vigorous levels of PA as assessed by accelerometry (Spearman r = .65, p < .001) and was responsive to an intervention-induced change in PA at 6 months when comparing the Cooperative Lifestyle Intervention Program-II walking and weight loss group with the weight loss only group (p < .001).

CONCLUSION

The MAT-W is a brief, reliable, and valid tool to assess PA and has promise for the assessment of walking behavior in older adults under free-living conditions.

Association between toe grasping strength and accelerometer-determined physical activity in middle-aged and older women

[Purpose] To test the hypothesis that toe grasping strength is associated with daily physical activity in older adults. [Subjects] Fifty-seven Japanese women, aged 52-78 years, volunteered. [Methods] Toe grasping and knee extension strength were measured. Physical activity was also measured, using an accelerometer, and the total duration of each level of exercise intensity (light, moderate, and vigorous) and average step counts were calculated. Subjects were separated into two groups on the basis of accelerometer-determined step counts: LOW (n=28, <8000 steps/day) and HIGH (n=29, ≥8000 steps/day). [Results] Body mass index and body composition (% fat and fat-free mass) were similar between the two groups. Absolute and relative toe grasping strengths (divided by body weight) were greater in HIGH than in LOW. However, both absolute and relative knee extension strength were similar between the groups. Relative toe grasping and knee extension strength correlated with all 3 intensities of physical activity and average step count. After adjusting for age, the duration of light plus moderate physical activity and average step counts correlated to toe grasping strength but not to knee extension strength. [Conclusion] Our results suggest that toe grasping strength may be associated with the amount of light intensity daily physical activity.

Objectively measured physical activity and inflammatory cytokine levels in middle-aged Japanese people

OBJECTIVE

Studies using self-reported physical activity (PA) showed that higher PA is associated with lower circulating levels of C-reactive protein; in contrast, studies investigating associations of objective PA and other inflammatory markers are limited. We investigated cross-sectional associations of accelerometer-determined PA with circulating levels of myokine-type inflammatory cytokines in a middle-aged Japanese population.

METHOD

A total of 1838 individuals (737 men and 1101 women) aged 40 to 69 years participated in the baseline survey of a population-based cohort study in Saga, Japan (2005-2007). Habitual PA was assessed by a single-axis accelerometer. Serum interleukin (IL)-4, IL-6, IL-8, IL-15, and tumor necrosis factor (TNF)-α were measured by a multiplex enzyme-linked immunosorbent assay. Associations between PA and cytokine levels were assessed by multiple regression analysis and analysis of covariance, with adjustment for potential confounders.

RESULTS

Step count and PA level (PAL) were inversely associated with TNF-α and IL-15 even after adjusting for BMI. Similarly, greater PA indices were also independently associated with a lower level of inflammatory cytokine z score as an index of overall inflammation.

CONCLUSION

The current results suggest that greater engagement in daily PA may be linked with reduced levels of myokine-type cytokines including IL-15, irrespective of body weight in middle-aged Japanese people.

Effect of FTO Gene and Physical Activity Interaction on Trunk Fat Percentage Among the Newfoundland Population

OBJECTIVE

To explore the effect of FTO gene and physical activity interaction on trunk fat percentage.

DESIGN AND METHODS

Subjects are 3,004 individuals from Newfoundland and Labrador whose trunk fat percentage and physical activity were recorded, and who were genotyped for 11 single-nucleotide polymorphisms (SNPs) in the FTO gene. Subjects were stratified by gender. Multiple tests and multiple regressions were used to analyze the effects of physical activity, variants of FTO, age, and their interactions on trunk fat percentage. Dietary information and other environmental factors were not considered.

RESULTS

Higher levels of physical activity tend to reduce trunk fat percentage in all individuals. Furthermore, in males, rs9939609 and rs1421085 were significant (α = 0.05) in explaining central body fat, but no SNPs were significant in females. For highly active males, trunk fat percentage varied significantly between variants of rs9939609 and rs1421085, but there is no significant effect among individuals with low activity. The other SNPs examined were not significant in explaining trunk fat percentage.

CONCLUSIONS

Homozygous male carriers of non-obesity risk alleles at rs9939609 and rs1421085 will have significant reduction in central body fat from physical activity in contrast to homozygous males of the obesity-risk alleles. The additive effect of these SNPs is found in males with high physical activity only.

Minute-by-minute stepping rate of daily physical activity in normal and overweight/obese adults

SUMMARY

The relationship between minute-by-minute stepping rate under free-living and obesity remains unclear. The purpose of the present investigation was to compare the levels of physical activity (PA) based on the minute-by-minute stepping rate under free-living conditions between normal weight (NW) and overweight and obese (OV) individuals. A total 40 volunteers participated in the present investigation. These participants were divided into NW or OV according to the body mass index (<25 kg m(-2) or 25 kg m(-2)). All participants wore a pedometer with a uni-axial accelerometer (Lifecorder-EX 4sec, Kenz, Japan) for 7 days continuously. The Lifecorder determined the number of steps and time spent in PA at <100, 100-129, 130 steps min(-1) according to the minute-by-minute stepping rate. The OV group took a significantly fewer number of steps per day in comparison to that in the NW group (p < 0.05). The average daily stepping rate was significantly lower in the OV group in comparison to that in the NW group (p = 0.01). Furthermore, the OV group spent a significantly shorter time in PA at a 100 steps min(-1) of the stepping rate compared with that in the NW group (p < 0.05). These results indicate that obese individuals spent significantly shorter time in PA at 100 steps min(-1) of stepping rate in comparison to the NW individuals.:

SVM versus MAP on accelerometer data to distinguish among locomotor activities executed at different speeds

Two approaches to the classification of different locomotor activities performed at various speeds are here presented and evaluated: a maximum a posteriori (MAP) Bayes' classification scheme and a Support Vector Machine (SVM) are applied on a 2D projection of 16 features extracted from accelerometer data. The locomotor activities (level walking, stair climbing, and stair descending) were recorded by an inertial sensor placed on the shank (preferred leg), performed in a natural indoor-outdoor scenario by 10 healthy young adults (age 25-35 yrs.). From each segmented activity epoch, sixteen features were chosen in the frequency and time domain. Dimension reduction was then performed through 2D Sammon's mapping. An Artificial Neural Network (ANN) was trained to mimic Sammon's mapping on the whole dataset. In the Bayes' approach, the two features were then fed to a Bayes' classifier that incorporates an update rule, while, in the SVM scheme, the ANN was considered as the kernel function of the classifier. Bayes' approach performed slightly better than SVM on both the training set (91.4% versus 90.7%) and the testing set (84.2% versus 76.0%), favoring the proposed Bayes' scheme as more suitable than the proposed SVM in distinguishing among the different monitored activities.

Physical activity in obesity and metabolic syndrome

Biological aging is typically associated with a progressive increase in body fat mass and a loss of lean body mass. Owing to the metabolic consequences of reduced muscle mass, it is understood that normal aging and/or decreased physical activity may lead to a higher prevalence of metabolic disorders. Lifestyle modification, specifically changes in diet, physical activity, and exercise, is considered the cornerstone of obesity management. However, for most overweight people it is difficult to lose weight permanently through diet or exercise. Thus, prevention of weight gain is thought to be more effective than weight loss in reducing obesity rates. A key question is whether physical activity can extenuate age-related weight gain and promote metabolic health in adults. Current guidelines suggest that adults should accumulate about 60 minutes of moderate-intensity physical activity daily to prevent unhealthy weight gain. Because evidence suggests that resistance training may promote a negative energy balance and may change body fat distribution, it is possible that an increase in muscle mass after resistance training may be a key mediator leading to better metabolic control.

Patterns of objectively measured physical activity in normal weight, overweight, and obese individuals (20-85 years): a cross-sectional study

BACKGROUND

The magnitude of the association between physical activity (PA) and obesity has been difficult to establish using questionnaires. The aim of the study was to evaluate patterns of PA across BMI-defined weight categories and to examine the independent contribution of PA on weight status, using accelerometers.

METHODS

The study was a cross-sectional population-based study of 3,867 adults and older people aged 20-85 years, living in Norway. PA was assessed for seven consecutive days using the ActiGraph GT1M accelerometer. Anthropometrical data was self-reported and overweight and obesity was defined as having a body mass index (BMI) of 25-<30 and ≥30 kg/m(2), respectively.

RESULTS

Overweight and obese participants performed less overall PA and PA of at least moderate intensity and took fewer steps, compared to normal weight participants. Although overall PA did not differ between weekdays and weekends, an interaction between BMI category and type of day was present, indicating a larger difference in overall PA between BMI categories on weekends compared to weekdays. Obese participants displayed 19% and 25% lower overall physical activity compared to normal weight participants, on weekdays and weekends, respectively. Participants in the most active quintile of overall PA had a 53% lower risk (OR 0.47, 95% CI: 0.37 to 0.60) for having a BMI above or below 25 kg/m(2), and a 71% lower risk (OR: 0.29, 95% CI: 0.20 to 0.44) for having a BMI above or below 30 kg/m(2).

CONCLUSIONS

Overweight and obese participants engaged in less overall PA and moderate and vigorous PA compared with normal weight individuals. The weight related differences in overall PA were most pronounced on the weekend and the risk of being overweight or obese decreases across quintiles of PA.

Patterns of physical activity and sedentary behavior in normal-weight, overweight and obese adults, as measured with a portable armband device and an electronic diary

BACKGROUND & AIMS

Accurate data on domain-specific physical activity and sedentary behavior among normal-weight, overweight and obese adults are scarce. This study described a comprehensive physical (in)activity profile and examined variations in activity across the week.

METHODS

Physical activity was measured in 442 Flemish adults (41.4 ± 9.8 years) for 7 days using the SenseWear Armband and an electronic diary. Differences in (in)activity between BMI subgroups were examined using one-way analyses of variance.

RESULTS

Physical activity level decreased with increasing BMI in men (1.77-1.46 MET) and women (1.67-1.31 MET). Sedentary time was higher in obese than normal-weight men (+1.09 h/day) and overweight and obese than normal-weight women (+1.04 and +1.88 h/day). Total hours of moderate-to-vigorous activity and bouts of moderate-to-vigorous activity were lower in overweight and obese than normal-weight subjects. The average duration of a sedentary bout and the number of breaks in sedentary time were only different between female BMI groups. The intensity of domain-specific activities decreased with increasing BMI. Activity patterns across the week differed between subgroups, with the difference most pronounced on Saturday for the male BMI groups.

CONCLUSIONS

This study described activity patterns among normal-weight, overweight and obese adults. The results should be used to design obesity prevention strategies.

Very short bouts of non-exercise physical activity associated with metabolic syndrome under free-living conditions in Japanese female adults

To assess the association between very short daily non-exercise physical activity (PA) lasting <5 min and metabolic syndrome (MS). A total of 42 females (50 ± 6 years) wore a pedometer with a one-axial accelerometer (Lifecorder, Kenz, Japan) to determine the time and the frequency of PA and the moderate to vigorous intensity PA (MVPA). In addition to the PA and the MVPA (PA(all) and MVPA(all)), the PA and MVPA were analyzed based on the bout duration, such as >32 s, >1 min, >3 min, and >5 min (PA(32S), PA(1M), PA(3M), PA(5M); MVPA(32S), MVPA(1M), MVPA(3M), MVPA(5M)). MS was defined according to the Japanese standard based on waist circumfluence, blood lipids, blood glucose, and blood pressure. The frequency of the MVPA(1M) was significantly lower in subjects with MS compared with that in subjects without MS (P < 0.05). The frequency of MVPA(32S) and MVPA(1M) was significantly associated with the HDL cholesterol (P < 0.05). The frequency of PA(3M) and PA(5M) was significantly associated with the fasting glucose level (P < 0.05). In contrast, we could not find any significant relationships between MS and the components of MS and the frequency of PA lasting <32 s. These results demonstrated that very short non-exercise PA, such as MVPA lasting >32 s to 3 min, has significantly associated with the components of MS. The specific advantages with regard to PA lasting <32 s remain unclear.

Ambulatory activity associations with cardiovascular and metabolic risk factors in smokers

BACKGROUND

We examined the association between ambulatory activity and biological markers of health in smokers.

METHODS

Baseline data from 985 subjects enrolled in a pharmacologic smoking cessation trial were examined. Body size, blood pressure, total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), total and small LDL particles, LDL size, high density lipoprotein cholesterol, triglycerides (TG), C-reactive protein (CRP), creatinine, fasting glucose, and hemoglobin A1c were assessed in relation to pedometer-assessed ambulatory activity, as was the odds of metabolic syndrome and CRP > 3 mg/L. Effect modification by gender was examined.

RESULTS

Only waist circumference was lower with greater steps/day in the men and women combined (P(trend) < 0.001). No other significant relationships were noted in men, while women with ≥ 7500 steps/day had lower weight, BMI, CRP, TG, total, and small LDL particles compared with those with < 7500 steps/day. These women also had 62% and 43% lower odds of metabolic syndrome and elevated CRP, respectively, compared with the less active women. Adjustment for BMI attenuated all the associations seen in women.

CONCLUSIONS

Greater ambulatory activity is associated with lower levels of metabolic and cardiovascular risk factors in female smokers which may, in part, be mediated by a reduction in BMI.

Quantification of the fragmentation of rest-activity patterns in elderly individuals using a state transition analysis

OBJECTIVES

Recent interest in the temporal dynamics of behavioral states has spurred the development of analytical approaches for their quantification. Several analytical approaches for polysomnographic data have been described. However, polysomnography is cumbersome, perturbs behavior, and is limited to short recordings. Although less physiologically comprehensive than polysomnography, actigraphy is nonintrusive, amenable to long recordings, and suited to use in subjects' natural environments, and provides an indirect measure of behavioral state. We developed a probabilistic state transition model to quantify the fragmentation of human rest-activity patterns from actigraphic data. We then applied this to the study of the temporal dynamics of rest-activity patterns in older individuals.

DESIGN

Cross-sectional.

SETTING

Community-based.

PARTICIPANTS

621 community-dwelling individuals without dementia participating in the Rush Memory and Aging Project.

MEASUREMENTS AND RESULTS

We analyzed actigraphic data collected for up to 11 days. We processed each record to give a series of transitions between the states of rest and activity, calculated the probabilities of such transitions, and described their evolution as a function of time. From these analyses, we derived metrics of the fragmentation of rest or activity at scales of seconds to minutes. Regression modeling of the relationship of these metrics with clinical variables revealed significant associations with age, even after adjusting for sex, body mass index, and a broad range of medical comorbidities.

CONCLUSIONS

Probabilistic analyses of the transition dynamics of rest-activity data provide a high-throughput, automated, quantitative, and noninvasive method of assessing the fragmentation of behavioral states suitable for large scale human and animal studies; these methods reveal age-associated changes in the fragmentation of rest-activity patterns akin to those described using polysomnographic methods.

The effect of weight monitoring and recording on control of obesity and overweight

BACKGROUND

Obesity is one of the dilemmas of the recent century and imposes huge costs related to its complications and diseases on people and societies. This study aims to investigate whether recording and monitoring weight and its changes can modify eating habits and therefore weight control.

METHODS

This is a quasi-experimental interventional study. Seventy nine of the staff of the University of Social Welfare and Rehabilitation (USWR) were randomly placed in two intervention (N=40) and control (39) groups. A standard weight scale and height meter was used to measure weight, height and body mass index (BMI). For the intervention group, weight was measured, recorded and announced to the participants twice a week for 3 months. For the control group, weight measurement and recording was done once in the beginning of the study and once at the end of the study. Data were analyzed using SPSS ver.11.5 and compared between groups.

RESULTS

There were no significant differences in the average age between the groups. Mean pre-intervention weight was 87.08±10.9 Kg and 85.83±16.44 Kg in the intervention and control groups, respectively and was not significantly different. Mean post-intervention weight was 83.5 Kg in the intervention group, which was significantly different from pre-intervention weight. Mean post-intervention weight was 86.31 Kg in the control group that was not significantly different from pre-intervention weight.

CONCLUSION

Recording and monitoring weight and its changes in overweight people can affect weight control since knowledge and insight about weight may motivate people to modify their eating habits. We therefore recommend this strategy as an adjuvant to weight control programs.

Influence of physical activity intensity and aerobic fitness on the anthropometric index and serum uric acid concentration in people with obesity

BACKGROUND AND OBJECTIVE

Physical activity (PA) is considered an important approach to prevent and treat obesity and hyperuricemia. The purpose of the present study was to examine the influence of PA intensity and aerobic fitness on anthropometric indices and serum uric acid in obese individuals.

METHODS

PA was examined using a single-axial accelerometer and aerobic fitness was assessed by electric cycle ergometry in obese middle-aged men (n=71, 47.2 ± 4.4 years). PA was defined as light (<3 metabolic equivalents [METs]), moderate (3.0-6.0 METs) or vigorous (>6.0 METs) intensity from the corresponding METs multiplied by time spent at the corresponding intensity levels. Serum uric acid was measured by the uricase peroxidase method.

RESULTS

The association between aerobic fitness index (lactate threshold) and serum uric acid did not reach statistical significance after adjustment for potential confounding factors (age, body mass index [BMI], and alcohol consumption) (β=-0.110, p=0.138). Light intensity PA was inversely associated with BMI and waist circumference, even after adjustment for age and alcohol consumption (BMI: β=-0.543, p=0.023; waist circumference: β=-1.333, p=0.016). Moderate intensity PA, but not light or vigorous intensity PA, was inversely correlated with the uric acid level and this remained significant after adjustment for age, BMI, and alcohol consumption (β=-0.222, p=0.036).

CONCLUSION

Our results suggest that light intensity PA may have an important role in weight control while moderate intensity PA may be associated with the lower uric acid concentrations in obese individuals.

The usefulness of an accelerometer for monitoring total energy expenditure and its clinical application for predicting body weight changes in type 2 diabetic korean women

BACKGROUND

The purpose of this study was to evaluate the usefulness of an accelerometer in predicting body weight (BW) change during a lifestyle intervention and to find out whether exercise or overall physical activity is associated with change in insulin sensitivity and body composition.

METHODS

A total of 49 overweight (body mass index [BMI] ≥ 23 kg/m(2)) women with diabetes were enrolled and performed lifestyle intervention while monitoring BW, total energy expenditure (TEE) and physical activity energy expenditure (PAEE) using an accelerometer, and energy intake (EI) using a three-day dietary record at baseline and every 2 weeks for 12 weeks. We assessed body composition using bioimpedance analysis and compared the actual BW change to the predicted BW change, which was calculated from the energy deficit (ED) between EI and TEE (ED = EI-TEE).

RESULTS

Mean age was 57.2 years, duration of diabetes was 8.0 years, and BMI was 27.8 kg/m(2). There was no significant difference between EI and TEE at baseline. For 12 weeks, the ED was 474.0 kcal·day(-1), which was significantly correlated with BW change (-3.1 kg) (r = 0.725, P < 0.001). However, the actual BW change was 50% lower than the predicted BW change. Both TEE and PAEE correlated with change in K(ITT) (r = 0.334, P = 0.019; r = 0.358, P = 0.012, respectively), BMI (r = -0.395, P = 0.005; r = -0.347, P = 0.015, respectively), and fat mass (r = -0.383, P = 0.007; r = -0.395, P = 0.005, respectively), but only TEE correlated with fat free mass change (r = -0.314, P = 0.030).

CONCLUSION

The accelerometer appears to be a useful tool for measuring TEE under free-living conditions for both short- and long-term periods.

An adaptive Kalman-based Bayes estimation technique to classify locomotor activities in young and elderly adults through accelerometers

An accelerometer-based system able to classify among different locomotor activities during real life conditions is here presented, and its performance evaluated. Epochs of walking at different speeds, and with different slopes, and stair descending and ascending, are detected, segmented, and classified by using an adaptation of a naïve 2D-Bayes classifier, which is updated on-line through the history of the estimated activities, in a Kalman-based scheme. The feature pair used for classification is mapped from an ensemble of 16 features extracted from the accelerometer data for each activity epoch. Two different versions of the classifier are presented to combine the multi-dimensional nature of the accelerometer data, and their results are compared in terms of correct recognition rate of the segmented activities, on two population samples of different age. The classification algorithm achieves correct classification rates higher than 90% and higher than 92%, for young and elderly adults, respectively.

Steps per day: the road to senior health?

In older adults, as in younger individuals, habitual moderate-intensity physical activity is associated with a reduced risk of various chronic health conditions, including certain types of cardiovascular and musculoskeletal disease and certain forms of cancer. However, the pattern of physical activity associated with such benefits remains unclear. One problem is that most investigators have examined patterns of physical activity using either subjective questionnaires or accelerometer or pedometer measurements limited to a single week, despite clear evidence of both the unreliability/invalidity of questionnaires and seasonal changes in activity patterns. Since 2000, we have thus conducted an interdisciplinary study examining the habitual physical activity and health of elderly people living in a medium-sized Japanese town (the Nakanojo Study). In about one-tenth of some 5000 available subjects aged > or =65 years, physical activity has already been assessed continuously for 24 h/day for >8 years using a specially adapted pedometer/accelerometer. This device has a storage capacity of 36 days and can distinguish >10 intensities of physical activity (expressed in metabolic equivalents [METs]). Data have to date been summarized as daily step counts and daily durations of activity of <3 and >3 METs, averaged over a 1-year period. This article provides a detailed overview of both factors influencing habitual physical activity and relationships between such activity and health in an elderly population. To date, analyses have been cross-sectional in type. Substantial associations have been noted between the overall health of participants and both the daily duration of effort undertaken at an intensity of >3 METs and the daily step count. In men, the extent of health is associated more closely with the daily duration of activity of >3 METs than with the daily step count, whereas in women, the association is closer for the step count than for the duration of activity >3 METs. In both sexes, the threshold amount of physical activity associated with better health is greater for physical than for mental benefits: >8000 versus >4000 steps/day and/or >20 versus >5 min/day at an intensity >3 METs, respectively. In other words, better physical health is seen in those spending at least 20 min/day in moderate walking (at a pace of around 1.4 m/s [5 km/h]) and a further >60 min of light activity per day. In contrast, better mental health is associated with much smaller amounts of deliberate physical activity. The daily step count and the daily durations of activity of <3 and >3 METs are all influenced by meteorological factors, particularly precipitation and mean ambient temperature. Activity decreases exponentially to about 4000 steps/day as precipitation increases. Excluding the influence of rainfall, the daily step count peaks at a mean outdoor temperature of around 17 degrees C; above and especially below such readings, physical activity decreases as a quadratic function of temperature. Seasonal changes in microclimate should thus be considered when designing interventions intended to increase the habitual physical activity of elderly people. The observed associations between physical activity and health outcomes point to a need for longitudinal analyses; these should examine potential causal interpretations of the current findings and elucidate possible additional mediating variables.

Gene X environment interaction of vigorous exercise and body mass index among male Vietnam-era twins

BACKGROUND

Secular trends over the past several decades suggest an environmental influence on body mass index (BMI). However, twin models that incorporate a gene-environment correlation and gene x environment interaction have not been applied to elucidate specific environmental factors that affect the heritability of BMI.

OBJECTIVE

Our aim was to determine whether one putative environmental predictor of obesity, vigorous exercise, shows evidence of a gene-environment correlation or gene x environment interaction with BMI among twins.

DESIGN

Twin structural equation modeling was used to examine a gene-environment correlation and a gene x environment interaction of vigorous exercise with BMI among 2710 monozygotic and 2327 dizygotic male-male twin pairs from the Vietnam Era Twin Registry -- a national registry of twin pairs who served in the military during the Vietnam War era.

RESULTS

Vigorous exercise significantly modified the additive genetic component of BMI, which indicated a gene x environment interaction (P < 0.001). BMI showed the greatest genetic influence among those who did not report vigorous exercise, with diminished genetic influence among those who did. Furthermore, vigorous exercise had a small but significant environmental effect on BMI (P = 0.006) -- a finding confirmed among monozygotic co-twins discordant for vigorous exercise.

CONCLUSIONS

Genetic influences on BMI are lower among those who report vigorous exercise. Consistent with an emerging literature, this suggests that vigorous exercise may mitigate some of the genetic influence on obesity. Molecular genetic studies of obesity should consider incorporating measures of behavioral and demographic factors to maximize the identification of novel obesity genes.

Using three objective criteria to examine pedometer guidelines for free-living individuals

The purpose was to examine in free-living individuals from a high-density city (1) the objectively determined physical activity levels across quartiles derived from pedometer step counts, (2) the pedometer steps day(-1) required to meet health-enhancing guidelines of accruing 30 min day(-1) of moderate physical activity and (3) the agreement between three objective criteria for the pedometer guidelines. Over 7 days 49 Hong Kong Chinese aged 15-55 years (n = 30 males) wore a polar heart rate monitor (HRM), an MTI and Tritrac accelerometer, plus a Yamax pedometer for >or=600 min day(-1). Participants averaged 9,839 +/- 3,088 steps day(-1), whilst accumulating 44.5 +/- 22.6, 43.1 +/- 21.7, and 24.7 +/- 19.3 min day(-1) of moderate physical activity by the Tritrac, MTI and HRM, respectively. Significant differences between quartiles of pedometer-determined activity were predominantly seen in the accelerometry data, especially during moderate and moderate-to-vigorous intensity activity (effect sizes >1.5 between upper and lower quartiles), but not seen in the HRM data. Using both criterion accelerometer datasets, a threshold of 8,000 steps day(-1) accurately categorized approximately 90% of those achieving, and approximately 80% of those not achieving, 30 min day(-1) of appropriate activity. They also produced a screening sensitivity of approximately 95% and a specificity of approximately 70%, which were considerably higher than those from the HRM data. Overall, the agreement between the three criterion measures suggests 8,000 steps day(-1) might be a valid screening tool as a proxy for classifying those meeting public health physical activity recommendations of 30 min day(-1) of moderate activity.