Measures Of Sedentary Behaviour Research Articles

Sedentary behavior in Brazilian children and adolescents: a systematic review.

ABSTRACTOBJECTIVE To describe the methodological characteristics of the studies selected and assess variables associated with sedentary behavior in Brazilian children and adolescents.METHODS For this systematic review, we searched four electronic databases: PubMed, Web of Knowledge, LILACS, SciELO. Also, electronic searches were applied in Google Scholar. A supplementary search was conducted in the references lists of the included articles and in non-indexed journals. We included observational studies with children and adolescents aged from three to 19 years developed in Brazil, presenting analyses of associations based on regression methods and published until September 30, 2014.RESULTS Of the 255 potential references retrieved by the searches, 49 met the inclusion criteria and composed the descriptive synthesis. In this set, we identified a great number of cross-sectional studies (n = 43; 88.0%) and high methodological variability on the types of sedentary behavior assessed, measurement tools and cut-off points used. The variables most often associated with sedentary behavior were “high levels of body weight” (in 15 out of 27 studies; 55.0%) and “lower level of physical activity” (in eight out of 16 studies; 50.0%).CONCLUSIONS The findings of this review raise the following demands to the Brazilian agenda of sedentary behavior research geared to children and adolescents: development of longitudinal studies, validation of measuring tools, establishment of risk cut-offs, measurement of sedentary behavior beyond screen time and use of objective measures in addition to questionnaires. In the articles available, the associations between sedentary behavior with “high levels of body weight” and “low levels of physical activity” were observed in different regions of Brazil.

Association of Sedentary Behaviour and Cardiometabolic Risk Biomarkers among Chinese Females: A Cross-sectional Study

Introduction: Recent epidemiologic evidence suggests that long-term health consequences are related to habitual sedentary behaviour. Sedentary lifestyles are greatly influenced by increasing technological interaction and involvement among the young adults. Because of the prognostic importance of cardio metabolic risk biomarkers on health and mortality this knowledge could provide an insight into the mechanisms through which sedentary behavior influences cardiovascular disease risk among Chinese females. However, there has been no thorough exploration of the independent contributions of sedentary behaviour to metabolic risk factors among Chinese females and the relative importance of these factors. Objective: The purpose of this study was to determine the association between sedentary behaviour and anthropometric measures among Chinese females. Method: 210 Chinese females participated in this cross sectional study. Sedentary Behaviour Questionnaire was used to assess their sedentary behaviour and height, weight, waist and hip measurements were made. Multivariate linear regression analyses examined associations of self-reported sedentary behaviour with biomarkers. Results: The highest sedentary behaviour engaged by the participants was doing paperwork or computer work, sitting ranked second and listening to music and the third being sitting reading book or magazine. The least sedentary behaviour that participants engaged was doing artworks or crafts. There was no significant association between sedentary behaviour and anthropometric measurements among Chinese females. Conclusion: The study concluded that sedentary behaviour is not detrimentally associated with waist circumference, BMI and waist-hip ratio among young Chinese females. It is possible that factors not directly accounted for in our analysis could have contributed to the healthy range of cardiometabolic risk biomarkers.

Waist Circumference and Objectively Measured Sedentary Behavior in Rural School Adolescents.

Research on relationships between lifestyle behaviors and adiposity in school youth is potentially important for identifying subgroups at risk. This study evaluates the associations between waist circumference (WC) and objective measures of sedentary behavior (SB) in a sample of rural school adolescents. The sample included 254 students (114 boys, 140 girls), 13-16 years of age, from rural regions of the Portuguese midlands. Height, weight, and WC were measured. Cardiorespiratory fitness (CRF) was assessed with the 20-m shuttle-run test. An uniaxial GT1M accelerometer was used to obtain 5 consecutive days of physically activity (PA) and SB. Multiple linear regression was used to test associations between WC and SB, adjusted for several potential confounders (age, sex, PA, CRF, parental education). SB was not significantly associated with the WC, neither in the unadjusted model nor after adjustment for all potential confounders. In the final model, the unique significant predictor of the WC was cardiorespiratory fitness (β = -0.82; 95% confidence interval [CI], -1.02 to -0.62). WC was not independently associated with SB time in rural school adolescents. Future research is claimed among rural adolescents in different geographic contexts to try to clarify recent findings of less studied communities.

Criterion Validity of the activPAL Activity Monitor for Sedentary and Physical Activity Patterns in People Who Have Rheumatoid Arthritis.

Accurate measurement of physical activity and sedentary behavior is an important consideration for health care professionals. The activPAL activity monitor has not been validated against a criterion measure for people with rheumatoid arthritis (RA). The objective of this study was to determine the criterion validity of the activPAL activity monitor for measuring step counts, transition counts, and time spent in sedentary, standing, and walking behaviors in people with RA. A laboratory-based criterion validation study was conducted. Participants with a confirmed medical diagnosis of RA were recruited from 2 outpatient rheumatology clinics. The testing procedure consisted of standardized testing components and tasks related to activities of daily living. Participants wore an activPAL activity monitor and were video recorded throughout the testing procedure. Direct observation was used as the criterion measure. Data analysis consisted of validation analysis of the activPAL activity monitor data and the criterion measure data. Twenty-four people participated in the study. Data from 20 participants were included in the final analysis. The activPAL significantly underestimated step counts by 26% and transition counts by 36%. There was no significant difference between the activPAL activity monitor and the criterion measure for time spent in sedentary, standing or light activity, and walking behaviors. Validation of activities of daily living in a laboratory environment is a limitation of this study. The activPAL activity monitor underestimated step and transition counts and, therefore, is not valid for measuring these outcomes in people with RA. Relative to direct observation, the activPAL activity monitor is valid for measuring time spent in sedentary, standing, and walking behaviors in people with RA.

A Randomised Controlled Trial to Reduce Sedentary Time in Young Adults at Risk of Type 2 Diabetes Mellitus: Project STAND (Sedentary Time ANd Diabetes).

AimsType 2 diabetes mellitus (T2DM), a serious and prevalent chronic disease, is traditionally associated with older age. However, due to the rising rates of obesity and sedentary lifestyles, it is increasingly being diagnosed in the younger population. Sedentary (sitting) behaviour has been shown to be associated with greater risk of cardio-metabolic health outcomes, including T2DM. Little is known about effective interventions to reduce sedentary behaviour in younger adults at risk of T2DM. We aimed to investigate, through a randomised controlled trial (RCT) design, whether a group-based structured education workshop focused on sitting reduction, with self-monitoring, reduced sitting time.MethodsAdults aged 18–40 years who were either overweight (with an additional risk factor for T2DM) or obese were recruited for the Sedentary Time ANd Diabetes (STAND) RCT. The intervention programme comprised of a 3-hour group-based structured education workshop, use of a self-monitoring tool, and follow-up motivational phone call. Data were collected at three time points: baseline, 3 and 12 months after baseline. The primary outcome measure was accelerometer-assessed sedentary behaviour after 12 months. Secondary outcomes included other objective (activPAL) and self-reported measures of sedentary behaviour and physical activity, and biochemical, anthropometric, and psycho-social variables.Results187 individuals (69% female; mean age 33 years; mean BMI 35 kg/m2) were randomised to intervention and control groups. 12 month data, when analysed using intention-to-treat analysis (ITT) and per-protocol analyses, showed no significant difference in the primary outcome variable, nor in the majority of the secondary outcome measures.ConclusionsA structured education intervention designed to reduce sitting in young adults at risk of T2DM was not successful in changing behaviour at 12 months. Lack of change may be due to the brief nature of such an intervention and lack of focus on environmental change. Moreover, some participants reported a focus on physical activity rather than reductions in sitting per se. The habitual nature of sedentary behaviour means that behaviour change is challenging.Trial RegistrationControlled-Trials.com ISRCTN08434554

Validation of Accelerometer Thresholds and Inclinometry for Measurement of Sedentary Behavior in Young Adult University Students.

Sedentary behavior (SB) is a major contributor to obesity and significant morbidity and mortality in adolescence and adulthood, yet measurement of SB is still evolving. The purpose of this study was to assess the degree of construct validity of the inclinometer function and single-axis and vector magnitude accelerometry metrics of the ActiGraph GT3X+ in objectively measuring SB and physical activity in 28 young adult university students who performed nine semi-structured activities, each for five minutes: lying, sitting, reading, seated video gaming, video watching, seated conversation, standing, stationary biking, and treadmill walking. Inclinometry and four output metrics from the ActiGraph were analyzed in comparison to direct observation by a researcher recorded each minute. For overall accuracy in measuring both SB and physical activity, all four accelerometer metrics (94.7-97.8%) outperformed the inclinometer function (70.9%). Vector magnitude accelerometry with a threshold of 150 counts per minute as the cut point for sedentary behavior was superior to other methods. While accelerometry was more accurate overall at detecting the behaviors tested, inclinometry had some advantages over accelerometry methods at detecting walking, biking, and standing. The findings support use of accelerometry as a valid objective measure of body movement, while use of inclinometry as a sole measure is not recommended. Additional research would be beneficial to improve the calibration of the inclinometer and explore ways of combining this with accelerometer data for objectively measuring SB and physical activity.

Validity of self-reported sedentary time differs between Australian rural men engaged in office and farming occupations

ABSTRACTRural Australians have a higher likelihood of chronic disease than urban Australians, particularly male farmers. Chronic disease has been associated with occupational sedentary time. The aim was to validate the self-report of sedentary time in men in contrasting rural occupations. Farmers (n = 29) and office workers (n = 28), age 30–65 years, were recruited from the Riverland region of South Australia. Daily sedentary time and number of breaks in sedentary time were self-reported and measured objectively using body-worn inclinometers. Correlational analyses were conducted between self-reported and objectively measured variables, separately by occupation. There was a significant correlation between self-reported and objectively measured sedentary time in the whole sample (r = 0.44, P = 0.001). The correlation among office workers was significant (r = 0.57, P = 0.003) but not among farmers (r = 0.08, P = 0.68). There were no significant correlations between self-reported and measured number of breaks in sedentary time, for the whole sample (rho = −0.03, P = 0.83), office workers (rho = 0.17, P = 0.39) and farmers (rho = −0.22, P = 0.25). In conclusion, the validity of self-report of sedentary behaviours by farmers was poor. Further research is needed to develop better performing self-report instruments or more accessible objective measures of sedentary behaviour in this population.

Lifestyle Behaviors in Metabolically Healthy and Unhealthy Overweight and Obese Women: A Preliminary Study.

BackgroundFew studies have examined dietary data or objective measures of physical activity (PA) and sedentary behavior among metabolically healthy overweight/obese (MHO) and metabolically unhealthy overweight/obese (MUO). Thus, the purpose is to determine whether PA, sedentary behavior and/or diet differ between MHO and MUO in a sample of young women.MethodsForty-six overweight/obese (BMI ≥25 kg/m2) African American and Caucasian women 19–35 years were classified by cardiometabolic risk factors, including elevated blood pressure, triglyceride, glucose and C-reactive protein, low high density lipoprotein, and insulin resistance (MUO ≥2; MHO, <2). Time (mins/day) in light, moderate, vigorous PA, and sedentary behavior were estimated using an accelerometer (≥3 days; ≥8 hrs wear time). Questionnaires were used to quantify sitting time, TV/computer use and usual daily activity. The Block Food Frequency Questionnaire assessed dietary food intake. Differences between MHO and MUO for lifestyle behaviors were tested with linear regression (continuous data) or logistic regression (categorical data) after adjusting for age, race, BMI, smoking and accelerometer wear and/or total kilocalories, as appropriate.ResultsWomen were 26.7±4.7 years, with a mean BMI of 31.1±3.7 kg/m2, and 61% were African American. Compared to MUO (n = 9), MHO (n = 37; 80%) spent less mins/day in sedentary behavior (difference: -58.1±25.5, p = 0.02), more mins/day in light PA (difference: 38.2±16.1, p = 0.02), and had higher daily METs (difference: 0.21±0.09, p = 0.03). MHO had higher fiber intakes (g/day of total fiber, soluble fiber, fruit/vegetable fiber, bean fiber) and daily servings of vegetables; but lower daily dairy servings, saturated fat, monounsaturated fat and trans fats (g/day) compared to MUO.ConclusionCompared to MUO, MHO young women demonstrate healthier lifestyle habits with less sedentary behavior, more time in light PA, and healthier dietary quality for fat type and fiber. Future studies are needed to replicate findings with larger samples that include men and women of diverse race/ethnic groups.

Utility of field-based techniques to assess Indigenous Australians' functional fitness and sedentary time

ObjectiveTo examine the utility of field-based techniques to assess functional exercise capacity and sedentary time in Indigenous and non-Indigenous regional Australian adults. Study designObservational, analytic cohort study. MethodsNinety six adults residing in regional and remote Australian communities participated in this study (Indigenous n = 61 and non-Indigenous Australians n = 35). Participants undertook a field-based test of functional exercise capacity (6 min walk test; 6 MWT) and wore an accelerometer during waking hours for seven days, provided self-report data on physical activity and sedentary time and rated experiences in regard to the ease of complying with study protocols. ResultsThere were high levels of compliance in this study (Indigenous: 91% and non-Indigenous: 97%). Functional exercise capacity was lower in Indigenous Australians (P < 0.001), and independently associated with advancing age, higher BMI, and indigeneity, with 45% of variability in the 6 MWT distance explained by these factors. The relationship between accelerometer and self-report measures of sedentary behaviour was significant (P < 0.001) but only explained 17% of the total variation. ConclusionsThis study demonstrated very good compliance for the methods utilised and is the first to report reduced functional exercise capacity in Indigenous people. ImplicationsThe field-based techniques from this study demonstrate good utility for larger scale implementation in regional Indigenous populations.

Independent Associations Between Sedentary Behaviors and Mental, Cognitive, Physical, and Functional Health Among Older Adults in Retirement Communities

We examined the relationships between objective and self-reported sedentary time and health indicators among older adults residing in retirement communities. Our cross-sectional analysis used data from 307 participants who completed baseline measurements of a physical activity trial in 11 retirement communities in San Diego County. Sedentary time was objectively measured with devices (accelerometers) and using self-reports. Outcomes assessed included emotional and cognitive health, physical function, and physical health (eg, blood pressure). Linear mixed-effects models examined associations between sedentary behavior and outcomes adjusting for demographics and accelerometer physical activity. Higher device-measured sedentary time was associated with worse objective physical function (Short Physical Performance Battery, balance task scores, 400-m walk time, chair stand time, gait speed), self-reported physical function, and fear of falling but with less sleep disturbance (all ps < .05). TV viewing was positively related to 400-m walk time (p < .05). Self-reported sedentary behavior was related to better performance on one cognitive task (trails A; p < .05). Sedentary time was mostly related to poorer physical function independently of moderate-to-vigorous physical activity and may be a modifiable behavior target in interventions aiming to improve physical function in older adults. Few associations were observed with self-reported sedentary behavior measures.

Issues and Challenges in Sedentary Behavior Measurement

Previous research has shown the negative impact of sedentary behavior on health, including cardiovascular risk factors, chronic disease-related morbidity, and mortality. Accurate measurement of sedentary behavior is thus important to plan effective interventions and to inform public health messages. This article (a) provides an overview of the nature and importance of sedentary behavior, (b) describes measurement methods, including subjective and objective measurement tools, (c) reviews the most important measurement and data processing issues and challenges facing sedentary behavior researchers, and (d) presents key findings from the most recent sedentary behavior measurement-related research. Both subjective and objective measures of sedentary behavior have limitations for obtaining accurate sedentary behavior measurements compliant with the current definitions of sedentary behavior, especially when investigating sedentary behavior as part of the full spectrum of physical behaviors. Regardless of the sedentary behavior measure chosen, researchers must be aware of all possible sources of error inherent to each technique and minimize those errors, thereby increasing validity of the outcome data.

Sensitivity to Change of Objectively-Derived Measures of Sedentary Behavior

The aim of this study was to examine the sensitivity to change of measures of sedentary behavior derived from body worn sensors in different intervention designs. Results from two intervention studies: Stand up for Your Health (pre-post home-based study with older adults not in paid employment) and Stand Up Comcare (non-randomized controlled trial in the workplace) were analyzed to quantify sensitivity to change of measures of total and accumulation of sedentary time obtained from hip-worn Actigraph and thigh-worn activPAL monitors. Sensitivity to change varied with intervention design and population considered. The activPAL was generally more sensitive but not consistently for all measures and designs. Measures of sedentary time accumulation, in particular half-life bout duration (W50%), were consistently more sensitive than total sedentary time. Measurement devices used in intervention studies need to be appropriately selected to be sensitive to changes in the behavioral target. For sedentary behavior interventions, measures of accumulation should be considered as outcomes.

Issues Related to Measuring and Interpreting Objectively Measured Sedentary Behavior Data

The use of objective measures of sedentary behavior has increased over the past decade; however, as is the case for objectively measured physical activity, methodological decisions before and after data collection are likely to influence the outcomes. The aim of this article is to review the evidence on different methodological decisions made by researchers when examining sedentary behavior. The different issues researchers may encounter when measuring sedentary behavior have been divided into (a) activity monitor placement; (b) epochs, cut points, and non-wear time definitions; (c) criteria for sedentary behavior bouts and breaks; and (d) combining motion and posture data. This article recommends that (a) activity monitors should be placed on the thigh and combined with a data reduction approach that estimates inclination, especially in children and adults; and (b) researchers should clearly report their data processing decisions to enhance the ability to evaluate and compare studies in the future. However, the article also highlights a dearth of methodological evidence to inform the use of objective measures of sedentary behavior. Based on the gaps in the literature, research recommendations, which require addressing to develop a best practice protocol when measuring sedentary behavior objectively, have been made.

The descriptive epidemiology of daily sitting time as a sedentary behavior in multiple sclerosis

BackgroundSedentary behavior is pervasive among the general population, but little is known about the epidemiology of this behavior in multiple sclerosis (MS). ObjectiveWe compared self-reported sitting time (ST), as a measure of sedentary behavior, between persons with MS and healthy controls, and examined ST across demographic and clinical characteristics of those with MS. Methods1081 persons with MS and 150 healthy controls self-reported ST based on the International Physical Activity Questionnaire (IPAQ), and completed the Godin Leisure-Time Exercise Questionnaire (GLTEQ) and a demographic/clinical scale. Data were analyzed using analysis of variance, bivariate correlations, and stepwise regression analysis. ResultsThere was not a significant difference in ST between persons with MS and controls (F = 0.01, p = 0.95), and persons with MS reported 450.9 ± 220.6 min of ST per day. ST was weakly associated with GLTEQ scores in MS (r = −0.21, p < 0.001), but not controls. ST significantly differed as functions of marital status, physical activity level, employment status, education, and degree of ambulatory impairment among those with MS. ConclusionsST does not differ between persons with MS and healthy controls, but those with MS report a large amount of this sedentary behavior that is potentially an independent correlate of health and disease outcomes.

Prospective association between objective measures of childhood motor coordination and sedentary behaviour in adolescence and adulthood.

BackgroundHigher levels of gross motor coordination are positively associated with physical activity in childhood, but little is known about how they relate to sedentary behaviour. The aim of this study was to investigate the longitudinal association between gross motor coordination at childhood and sedentary behaviour in adolescence and adulthood.MethodsData were from the 1970 British Cohort Study (the age 10, 16, and 42-year surveys). At age 10 the participant’s mother provided information on how often participants watched TV and played sports and a health visitor administered several tests to assess gross motor coordination. At aged 16 and 42-years participants reported their daily screen and TV time, respectively, and physical activity status. We examined associations between gross motor coordination at age 10 with sedentary behaviour and physical activity at age 16 and 42, using logistic regression.ResultsIn multivariable models, higher levels of gross motor coordination were associated with lower odds of high screen time (n = 3073; OR 0.79, 95 % CI 0.64, 0.98) at 16-years although no associations with physical activity were observed (OR 1.16, 95 % CI 0.93, 1.44). Similar associations were observed with TV time in adulthood when participants were aged 42, and in addition high gross motor coordination was also associated with physical activity participation (n = 4879; OR 1.18, 95 % CI 1.02, 1.36).ConclusionsIntervention efforts to increase physical activity participation and reduce sedentary behaviour over the life course may be best targeted towards children with low gross motor coordination.Electronic supplementary materialThe online version of this article (doi:10.1186/s12966-015-0236-y) contains supplementary material, which is available to authorized users.

Novel strategies for sedentary behavior research.

This article reports on the "Novel Strategies for Sedentary Behavior Research" session of the Sedentary Behavior: Identifying Research Priorities workshop. The purpose of this session of the workshop were to propose strategies for accomplishing a research agenda in dealing with sedentary behavior and to consider research priorities for people at high risk for excess sedentary behavior. The four major recommendations from this workshop were as follows: 1) To add repeated objective measures of physical activity and sedentary behavior to existing cohort studies and standardize approaches to measurement and analysis. Epidemiologic studies will be the most efficient design for addressing some research questions. 2) To increase research efficiency, consider the advantages of a network of connected research studies and health systems. Advantages include access to existing data in electronic health records. 3) To carefully select a variety of high-risk study populations and preplan collaboration among studies in intervention research. This strategy can efficiently address the breadth of issues in sedentary behavior research. 4) To include comparative effectiveness designs and pure environmental interventions in intervention research. This strategy facilitates and enhances translation of interventions into practice.

Sedentary Behavior Research Priorities--NHLBI/NIA Sedentary Behavior Workshop Summary.

Over the course of 2013, the National Heart, Lung and Blood Institute (NHLBI) and the National Institute on Aging (NIA) collaborated with a multi-national group of expert scientists to convene, host and facilitate a four-part virtual webinar workshop on sedentary behavior. Participants met to evaluate and discuss the current epidemiological, clinical and other relevant literature on sedentary behavior and to identify research priorities relative to preventing cardiovascular disease and mitigating aging-related disability and functional outcomes. The workshop was predicated on findings of insufficient levels of population adherence to current physical activity recommendations (1,12) and the need to address the NHLBI and NIA research portfolio gaps in the area of sedentary behavior.

Objective measurement of sedentary behavior: impact of non-wear time rules on changes in sedentary time.

BackgroundAccelerometry non-wear time rules might affect sedentary time, and the associations with health outcomes such as adiposity. However, the exact effect of different non-wear time rules on sedentary time and reported changes in sedentary time is unknown. This study evaluated the effect of different accelerometry non-wear time rules on sedentary time and changes in sedentary time from age 9–12 years.MethodsAccelerometry data were collected as part of the Gateshead Millennium Birth Cohort study. Participants were 9.3 (±0.4) years at baseline (n = 517) and 12.5 (±0.3) years at follow-up (n = 440). Sedentary time was defined using an accelerometry cut-point of 25 counts per 15 s. Non-wear time was defined using manual data reduction (the reference method) and 10 min, 20 min and 60 min consecutive zeros. Differences between methods were analyzed using repeated measures ANOVA with Bonferroni post-hoc analyses.ResultsMean daily sedentary time at age 9 ranged from 364 min per day to 426 min using the 10 min and 60 min rule, respectively (p < 0.05). At 12 years, mean daily sedentary times ranged from 424 min to 518 min (p < 0.05). Mean changes in daily sedentary time over the three years ranged from 60 min to 93 min using the 10 min and 60 min rule, respectively (p < 0.05). When adjusting for wear time, differences in average sedentary time between methods decreased from 62 min to 27 min (age 9), 95 min to 32 min (age 12) and 33 min to 10 min (changes between 9 to 12 years).ConclusionsUsing different non-wear time rules results in significant differences in daily sedentary time and changes in sedentary time. Correcting for wear time appears to be a reasonable approach to limiting these differences and may improve comparability between future studies. Using the 20 min rule, while correcting for wear time, provided the most accurate estimates of sedentary time and changes in sedentary time, compared to the manual reference in 9–12 year-olds.

Effects of a DVD-delivered exercise intervention on physical function in older adults with multiple sclerosis: A pilot randomized controlled trial.

BackgroundOlder adults with multiple sclerosis (MS) exhibit disease-related impairments such as compromised strength, balance, mobility, coordination, and quality of life (QOL). Exercise training as an intervention to reverse these conditions in older adults with MS is limited.ObjectiveThe objective of this pilot trial was to examine the effects of a DVD exercise intervention targeting flexibility, strength, and balance in older adults with MS in order to generate effect sizes to power a larger trial.MethodsParticipants were randomly assigned to a six-month DVD exercise intervention (n = 24) or a healthy aging DVD control condition (n = 24). Measures of physical function, physical activity, sedentary behavior, QOL and program satisfaction were assessed at baseline and at follow-up.ResultsThe DVD exercise intervention was well received with no adverse events. Effects sizes ranged from small to modest reflecting improved function, increased physical activity, decreased sitting time, and improved QOL in the intervention condition compared to the control condition.ConclusionThis pilot randomized controlled trial suggests that older adults with MS are receptive to an exercise program via DVD, and the program results in modest but potentially important improvements in function and physical activity.

Metabolomic Correlates of Objectively Measured Physically Active and Sedentary Behaviors

PURPOSE: Physical activity (PA) is associated with a variety of non-communicable diseases, including certain cancers, but our understanding of the biological mechanisms underlying the observed associations remains incomplete. METHODS: We compared accelerometer-based measures of PA and sedentary behavior (SB) to 447 plasma metabolites using an untargeted metabolomics approach (Metabolon, Inc). Two groups of Chinese adults (N=339 total) were enrolled and measured in separate waves, one year apart. Participants wore an ActiGraph 7164 for 7-d on four occasions over 12-months to estimate habitual PA energy expenditure (PAEE, MET-hrs/d) and SB (hrs/d < 100 counts/min). Behavior-metabolite associations were modeled with linear regression adjusting for age, gender, body mass index (BMI), and smoking. RESULTS: Average age was 60 yrs, BMI was 23.8 kg/m2, PAEE was 11.0 MET-hrs/d SB duration was 8.7 hrs/d, and 54% of participants were women. PAEE was associated with 49 of 447 (11.0%) metabolites (p<0.05) and 22 had a false discovery rate of <20%. Notable metabolite associations included those with amino acids important for protein synthesis and energy metabolism (leucine, isoleucine, alanine), metabolites linked to insulin resistance and diabetes (2-hydroxybutyrate, mannose, glucose), obesity (glutamate), and metabolites involved in lipid, pentose, bile acid, carnitine, and xenobiotic metabolism. About 85% of the time, higher PAEE was associated with lower metabolite levels. SB was associated with 40 (8.9%) metabolites (p<0.05) and 14 of these had a false discovery rate of <20%. SB associations were largely reciprocal to those for PAEE. CONCLUSION: Overall, the pattern of association suggests a systematic lowering of metabolites involved in energy and nutrient metabolism in response to higher levels of habitual PA and/or lower levels of SB. Future work should replicate these findings in intervention trials and examine possible links to disease risk in prospective etiologic studies.