Sedentary behavior, recreational physical activity, and 7-year weight gain among postmenopausal U.S. women.

OBJECTIVE: To assess the relationship among recreational physical activity (PA), non-occupational sedentary behavior, and 7-year weight gain among postmenopausal U.S. women 40 to 69 years old. RESEARCH METHODS AND PROCEDURES: In 1992 and 1999, 18,583 healthy female participants from the Cancer Prevention Study II Nutrition Cohort completed questionnaires on anthropometric characteristics and lifestyle factors. The associations between recreational PA [in metabolic equivalent (MET) hours per week] and non-occupational sedentary behavior (in hours per day) at baseline and risk for 7-year weight gain (5 to 9 or >or =10 vs. +/-4 pounds) were assessed using multivariate logistic regression analysis.
RESULTS: Neither PA nor sedentary behavior was associated with a 5- to 9-pound weight gain. Among women who were not overweight at baseline (BMI <25.0), the odds of > or =10-pound weight gain were 12% lower (odds ratio, 0.88; 95% confidence interval, 0.77 to 0.99) for those in the highest category of recreational PA (> or =18 MET h/wk) compared with >0 to <4 MET h/wk; odds were 47% higher (odds ratio, 1.47; 95% confidence interval, 1.21 to 1.79) for non-overweight women who reported > or =6 h/d of non-occupational sedentary behavior compared with <3 h/d. Neither PA nor sedentary behavior were associated with risk of > or =10-pound weight gain weight among women who were overweight at baseline (BMI > or =25.0). DISCUSSION: Both recreational PA and non-occupational sedentary behavior independently predicted risk of > or =10-pound weight gain among postmenopausal women who were not overweight at baseline. Public health messages to prevent weight gain among normal-weight postmenopausal women may need to focus on decreasing time spent in sedentary behaviors and increasing the amount of time spent on PA.