Associations of Recreational and Nonrecreational Physical Activity and Body Weight Change on Cardiovascular Disease Mortality During the Obesogenic Transition in the United States: National Health and Nutrition Examination Survey Follow-up Study

Background: To investigate cardiovascular disease mortality associated with longitudinal changes in body weight, and recreational and nonrecreational physical activity during the obesogenic transition in the United States since the 1970s. Methods: Data were analyzed from 4921 individuals aged 25-74 years who participated in the National Health and Nutrition Examination Survey between 1971 and 1979 and follow-up studies to 1992. Mortality was confirmed by searching the National Death Index or proxy interview; clinical data were collected in person. Changes in self-reported recreational and nonrecreational physical activity categories over time were coded as stable, increase, or decrease. Competing risks regression was used to determine hazard ratios adjusted for covariates. A logit model in a generalization method was used to explore mediation effects of change in body weight. Results: Compared with the "moderate-vigorous stable" group (reference), individuals who remained inactive ("inactive stable") or reduced their participation in physical activity ("active to inactive") experienced the highest mortality, with a 50% to 176% and 22% to 222% relative increased hazard ratios for nonrecreational and recreational physical activity, respectively, across all models adjusted for covariates. This corresponded to significant loss of life (up to 3 y; all P < .05). Individuals who became active ("inactive to active") were not at increased risk. We found weak (but nonstatistically significant) evidence of mediation effects of body weight change on mortality. Conclusions: Longitudinal changes in moderate-vigorous recreational and nonrecreational physical activity were important predictors of cardiovascular disease mortality during the obesogenic transition period in the United States and were mostly unexplained by changes in body weight.