Objectively measured physical activity of USA adults by sex, age, and racial/ethnic groups: a cross-sectional study

<p>Abstract</p> <p>Background</p> <p>Accelerometers were incorporated in the 2003–2004 National Health and Nutritional Examination Survey (NHANES) study cycle for objective assessment of physical activity. This is the first time that objective physical activity data are available on a nationally representative sample of U.S. residents. The use of accelerometers allows researchers to measure total physical activity, including light intensity and unstructured activities, which may be a better predictor of health outcomes than structured activity alone. The aim of this study was to examine objectively determined physical activity levels by sex, age and racial/ethnic groups in a national sample of U.S. adults.</p> <p>Methods</p> <p>Data were obtained from the 2003–2004 NHANES, a cross-sectional study of a complex, multistage probability sample of the U.S. population. Physical activity was assessed with the Actigraph AM-7164 accelerometer for seven days following an examination. 2,688 U.S. adults with valid accelerometer data (i.e. at least four days with at least 10 hours of wear-time) were included in the analysis. Mean daily total physical activity counts, as well as counts accumulated in minutes of light, and moderate-vigorous intensity physical activity are presented by sex across age and racial/ethnic groups. Generalized linear modeling using the log link function was performed to compare physical activity in sex and racial/ethnic groups adjusting for age.</p> <p>Results</p> <p>Physical activity decreases with age for both men and women across all racial/ethnic groups with men being more active than women, with the exception of Hispanic women. Hispanic women are more active at middle age (40–59 years) compared to younger or older age and not significantly less active than men in middle or older age groups (i.e. age 40–59 or age 60 and older). Hispanic men accumulate more total and light intensity physical activity counts than their white and black counterparts for all age groups.</p> <p>Conclusion</p> <p>Physical activity levels measured objectively by accelerometer demonstrated that Hispanic men are, in general, more active than their white and black counterparts. This appears to be in contrast to self-reported physical activity previously reported in the literature and identifies the need to use objective measures in situations where the contribution of light intensity and/or unstructured physical activity cannot be assumed homogenous across the populations of interest.</p

Issues in accelerometer methodology: the role of epoch length on estimates of physical activity and relationships with health outcomes in overweight, post-menopausal women

<p>Abstract</p> <p>Background</p> <p>Current accelerometer technology allows for data collection using brief time sampling intervals (i.e., epochs). The study aims were to examine the role of epoch length on physical activity estimates and subsequent relationships with clinically-meaningful health outcomes in post-menopausal women.</p> <p>Methods</p> <p>Data was obtained from the Woman On the Move through Activity and Nutrition Study (n = 102). Differences in activity estimates presented as 60s and 10s epochs were evaluated using paired t-tests. Relationships with health outcomes were examined using correlational and regression analyses to evaluate differences by epoch length.</p> <p>Results</p> <p>Inactivity, moderate- and vigorous-intensity activity (MVPA) were significantly higher and light-intensity activity was significantly lower (all <it>P </it>< 0.001) when presented as 10s epochs. The correlation between inactivity and self-reported physical activity was stronger with 10s estimates (<it>P </it>< 0.03); however, the regression slopes were not significantly different. Conversely, relationships between MVPA and body weight, BMI, whole body and trunk lean and fat mass, and femoral neck bone mineral density was stronger with 60s estimates (all <it>P </it>< 0.05); however, regression slopes were similar.</p> <p>Conclusion</p> <p>These findings suggest that although the use of a shorter time sampling interval may suggestively reduce misclassification error of physical activity estimates, associations with health outcomes did not yield strikingly different results. Additional studies are needed to further our understanding of the ways in which epoch length contributes to the ascertainment of physical activity in research studies.</p> <p>Trial Registration</p> <p>Clinical Trials Identifier: NCT00023543</p

Social- and Behavioral-Specific Genetic Effects on Blood Pressure Traits: The Strong Heart Family Study

Population studies have demonstrated an important role of social, behavioral, and environmental factors in blood pressure levels. Accounting for the genetic interaction of these factors may help to identify common blood pressure susceptibility alleles

Measuring Physical Activity and Sedentary Behavior in Youth with Type 2 Diabetes.

Background: Lifestyle interventions that encourage increasing physical activity (PA) and losing weight are critical for overweight and obese youth with comorbid conditions. Assessing PA within such lifestyle intervention efforts requires measurement tool(s) that are both accurate and appropriate for these youth. This research compares PA levels and sedentary behavior in an ethnically diverse cohort of overweight/obese youth with type 2 diabetes using both accelerometry and a questionnaire previously validated in the general youth population. Methods: Spearman's correlations were used to compare time spent sedentary and in different PA intensities between a questionnaire, the three-day PA recall (3DPAR), and an objective PA measure, the ActiGraph accelerometer, in 236 overweight/obese youth with diabetes. Results: Spearman correlations between 3DPAR and accelerometer results for total PA were small and not significant (rho = 0.11, p > 0.05 for males and females). Correlations for specific PA intensities (moderate/vigorous and light) were also small and not significant. Sedentary time between instruments was significant, but weakly correlated in females (rho = 0.19, p < 0.05), but not in males (rho = 0.07, p = 0.48). Conclusions: Subjective PA measures validated in the general youth population may not be the best method for differentiating levels of movement in overweight/obese youth with type 2 diabetes, who spend most of their time in light-intensity activity and sedentary pursuits with little or no time spent in moderate/vigorous-intensity activities. Objective measures such as accelerometers that can capture the lower end of the movement scale are likely the more appropriate measures under these conditions

Activity and Sedentary Time 10 Years After a Successful Lifestyle Intervention : The Diabetes Prevention Program

Introduction: This study aims to determine if evidence exists for a lasting effect of the Diabetes Prevention Program (DPP) lifestyle intervention on activity levels by comparing objectively collected activity data between the DPP Outcome Study (DPPOS) cohort and adults from the National Health and Nutrition Examination Survey (NHANES; 2003-2006). Methods: Average minutes/day of light and moderate to vigorous physical activity (MVPA) and sedentary behavior from ActiGraph accelerometers (collected 2010-2012) were examined (2013-2014) for comparable DPPOS and NHANES subgroups by age, sex, and diabetes status. Longitudinal questionnaire data on leisure activity, collected yearly from DPP baseline to the time of accelerometer measurement (1996-2010; 11.9-year mean follow-up), were also examined to provide support for a long-term intervention effect. Results: Average minutes/day of accelerometer-derived MVPA was higher in all DPPOS subgroups versus NHANES subgroups of similar age/sex/diabetes status; with values as much as twice as high in some DPPOS subgroups. Longitudinal questionnaire data from DPP/DPPOS showed a maintained increase of 1.24 MET hours/week (p=0.026) of leisure activity in DPPOS participants from all original study arms between DPP baseline and accelerometer recording. There were no consistent differences between comparable DPPOS and NHANES subgroups for accelerometer-derived sedentary or light-intensity activity minutes/day. Conclusions: More than 10 years after the start of DPP, DPPOS participants performed more accelerometer-measured MVPA than similar adults from NHANES. Longitudinal questionnaire data support the accelerometer-based findings by suggesting that leisure activity levels at the time of accelerometer recording remained higher than DPP baseline levels

Modest Levels of Physical Activity Are Associated With a Lower Incidence of Diabetes in a Population With a High Rate of Obesity: The Strong Heart Family Study

OBJECTIVE: To examine the association of objectively measured participation in low levels of physical activity with incident type 2 diabetes. RESEARCH DESIGN AND METHODS: The study population included participants free of diabetes and cardiovascular disease at baseline (n = 1,826) who participated in a follow-up examination. Generalized estimating equations were used to examine the association of steps per day with incident diabetes. RESULTS: During 5 years of follow-up, 243 incident cases of diabetes were identified. When compared with participants in the lowest quartile of steps per day (<3,500 steps), participants in the upper three quartiles of steps per day had lower odds for diabetes, consistent with a threshold effect. Contrasting the three upper quartiles with the lowest quartile, the odds ratio of diabetes was 0.71 (95% CI 0.51–0.98). CONCLUSIONS: Modest levels of physical activity are associated with a lower risk of incident diabetes, compared with lower levels of activity