Effects of moderate/vigorous activity on 3-year body composition changes in postmenopausal women: a target trial emulation.

Abstract Postmenopausal women experience significant changes in body composition, particularly abdominal adipose tissue (AAT) deposition patterns, which influence cardiometabolic risk. Physical activity has demonstrable effects on body composition and overall health; however, there is little evidence for how physical activity influences AAT patterns and body composition in postmenopausal women. We emulated a target trial of physical activity interventions, including the 2018 Physical Activity Guidelines for Americans recommendations (≥150 minutes/week), on 3-year changes in AAT and body composition. We analyzed data from 4451 postmenopausal women aged 50-79 years in the Women’s Health Initiative (WHI) with repeated whole body Dual X-Ray Absorptiometry (DXA) scans with derived abdominal visceral (VAT) and subcutaneous adipose tissue (SAT). The mean AAT and body composition measures were estimated with the parametric-g formula. Over 3 years, interventions of increasing minutes of moderate activity would result in dose-dependent reductions in AAT, overall body fat and increases in lean soft tissue, with the greatest estimated benefit at the 2018 physical activity guideline recommendations. Compared to no intervention, if all participants had adhered to ≥150 mins/week of moderate physical activity, they would have 16.8 cm2 lower VAT (95% CI: −23.1, −10.4), 26.8 cm2 lower SAT (95% CI: −36.3, −17.3), 1.3% lower total body fat (95% CI: −1.8, −0.7), 1.2% higher total lean soft tissue (95% CI: 0.7-1.8), and 2.6 kg lower bodyweight (95% CI, −3.6, −1.5). We saw similar patterns in vigorous-intensity activity interventions. These results suggest that postmenopausal women who adhere to physical activity guideline recommendations would experience beneficial body composition changes over 3 years.