Division of Cancer Epidemiology and Genetics, Nutritional Epidemiology Branch
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Accelerometer-measured dose-response for physical activity, sedentary time, and mortality in US adults
- Published on Oct 5, 2016
Background: Moderate-to-vigorous–intensity physical activity is recommended to maintain and improve health, but the mortality benefits of light activity and risk for sedentary time remain uncertain.
Objectives: Using accelerometer-based measures, we 1) described the mortality dose-response for sedentary time and light- and moderate-to-vigorous–intensity activity using restricted cubic splines, and 2) estimated the mortality benefits associated with replacing sedentary time with physical activity, accounting for total activity.
Design: US adults (n = 4840) from NHANES (2003–2006) wore an accelerometer for ≤7 d and were followed prospectively for mortality. Proportional hazards models were used to estimate adjusted HRs and 95% CIs for mortality associations with time spent sedentary and in light- and moderate-to-vigorous–intensity physical activity. Splines were used to graphically present behavior-mortality relation. Isotemporal models estimated replacement associations for sedentary time, and separate models were fit for low- (<5.8 h total activity/d) and high-active participants to account for nonlinear associations.
Results: Over a mean of 6.6 y, 700 deaths occurred. Compared with less-sedentary adults (6 sedentary h/d), those who spent 10 sedentary h/d had 29% greater risk (HR: 1.29; 95% CI: 1.1, 1.5). Compared with those who did less light activity (3 h/d), those who did 5 h of light activity/d had 23% lower risk (HR: 0.77; 95% CI: 0.6, 1.0). There was no association with mortality for sedentary time or light or moderate-to-vigorous activity in highly active adults. In less-active adults, replacing 1 h of sedentary time with either light- or moderate-to-vigorous–intensity activity was associated with 18% and 42% lower mortality, respectively.
Conclusions: Health promotion efforts for physical activity have mostly focused on moderate-to-vigorous activity. However, our findings derived from accelerometer-based measurements suggest that increasing light-intensity activity and reducing sedentary time are also important, particularly for inactive adults.
- Charles E Matthews 1
- Sarah Kozey Keadle 1
- Richard P Troiano 2
- Lisa Kahle 4
- Annemarie Koster 6
- Robert Brychta 5
- Dane Van Domelen 7
- Paolo Caserotti 7
- Kong Y Chen 5
- Tamara B Harris 8
- David Berrigan 3
Epidemiology and Genomics Research Program
Behavioral Research Program, Division of Cancer Control and Population Sciences, National Cancer Institute, Bethesda, MD
Information Management Services Inc., Silver Spring, MD
National Institute of Diabetes and Digestive and Kidney Diseases, Diabetes, Endocrinology, and Obesity Branch, Bethesda, MD
Care and Public Health Research Institute School for Public Health and Primary Care, Department of Social Medicine, Maastricht University, Maastricht, Netherlands
Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
National Institute on Aging, Intramural Research Program, Laboratory of Epidemiology, Demography, and Biometry, Bethesda, MD
The American Journal of Clinical Nutrition