Physical activity changes predict abdominal fat change in midlife women.

BACKGROUND The influence of physical activity (PA) changes on risk of abdominal fat gain in midlife women has not been studied using objective measures and controlling for potentially confounding variables. METHODS Changes in PA were assessed within a prospective cohort of 233 middle-age (40 +/- 3 years), nonobese, nonsmoking, primarily Caucasian women by using accelerometers, worn continuously for 7 consecutive days at baseline and again at a 20 month follow-up. Weighed food intake diaries were completed on concurrent days. Bod Pod assessed total body fat. Abdominal fat was measured by abdominal circumference at the umbilicus. RESULTS Women who decreased PA gained abdominal fat across 20 months, while women who increased PA (F = 4.82, P = .009) did not. Change in PA remained an independent predictor of abdominal fat change after adjusting for potential confounders, including changes in total body fat and total energy intake. Compared with women who maintained or decreased PA, women who increased PA had approximately half the risk (RR = 0.52, 95% CI: 0.27, 0.98) of gaining abdominal fat. CONCLUSIONS Increasing daily physical activity may attenuate risk of abdominal fat gain in middle-age women independent of changes in total body fat or energy intake.