Light-intensity physical activities and mortality in the United States general population and CKD subpopulation

Abstract

Background and objectives: Sedentary behavior is associated with increased mortality in the general population. Whether replacing sedentary behavior with low- or light-intensity activities confers a survival benefit in the general or CKD populations is unknown.

Design, setting, participants, & measurements: This observational analysis of the 2003-2004 National Health and Nutrition Examination Survey examined the associations of low- and light-intensity activities with mortality. On the basis of the number of counts/min recorded by an accelerometer, durations of sedentary (<100/min), low (100-499/min), light (500-2019/min), and moderate/vigorous (≥2020/min) activity were defined and normalized to 60 minutes. The mortality associations of 2 min/hr less sedentary duration in conjunction with 2 min/hr more (tradeoff) spent in one of the low, light, or moderate/vigorous activity durations while controlling for the other two activity durations were examined in multivariable Cox regression models in the entire cohort and in the CKD subgroup.

Results: Of the 3626 participants included, 383 had CKD. The mean sedentary duration was 34.4±7.9 min/hr in the entire cohort and 40.8±6.8 in the CKD subgroup. Tradeoff of sedentary duration with low activity duration was not associated with mortality in the entire cohort or the CKD subgroup. Tradeoff of sedentary duration with light activity duration was associated with a lower hazard of death in the entire cohort (hazard ratio, 0.67; 95% confidence interval, 0.48 to 0.93) and CKD subgroup (hazard ratio, 0.59; 95% confidence interval, 0.35 to 0.98). Tradeoff of sedentary duration with moderate/vigorous activity duration had a nonsignificant lower hazard in the entire cohort and CKD subgroup.

Conclusions: Patients with CKD are sedentary nearly two thirds of the time. Interventions that replace sedentary duration with an increase in light activity duration might confer a survival benefit.

Keywords: chronic kidney disease; obesity; quality of life.

Copyright © 2015 by the American Society of Nephrology.

Figures

Figure 1.

Distribution of physical activity intensity durations per 60 minutes. Normalized means are presented in the pie charts. Normalized medians and 25th and 75th percentiles are presented in box plots, and whiskers represent the 10th and 90th percentiles. MVPA, moderate/vigorous-intensity physical activity.

Figure 2.

Mortality associations with individual activity durations, without adjustment for other activities. Hazard ratios and 95% confidence intervals are presented. MVPA, moderate/vigorous-intensity physical activity.

Figure 3.

Mortality associations of tradeoff of 1–5 min/hr of sedentary duration with durations of low- or light-intensity activities. (A) Entire cohort. (B) CKD subgroup.