Obesity and Midlife Performance: A Cross‐Sectional and Longitudinal Analysis of Women in the Menarche‐To‐ PreMenopause Study

ABSTRACT Background The interplay between obesity and physical performance in women is poorly understood, especially before the fifties. Objective To assess associations between weight gain from early to mid‐adulthood and midlife performance‐based physical function. Methods 499 women from the Menarche‐to‐PreMenopause Study completed handgrip strength, chair rise, and standing balance tests at age 41–48. The lowest tertile was defined as the ‘worse performance’ group. Weight and height were self‐reported across eight surveys, from ages 18–23 to 40–45, and used to determine body mass index (BMI) trajectories using group‐based trajectory modelling, as well as to estimate annual weight gain percentages. Other obesity indicators included BMI, waist circumference (WC), and waist‐to‐hip ratio (WHR) measured cross‐sectionally at age 41–48. Results Two BMI trajectories were identified: Normal‐Increasing (75%) and High‐Increasing (25%). The High‐Increasing BMI trajectory showed approximately 40% higher prevalence of worse chair‐rise and standing‐balance performances compared to the Normal‐Increasing group (95% CI: 9%–84%, p = 0.01; and 10%–84%, p = 0.008). Higher annual weight gain percentage showed a prevalence ratio (PR) 1.21 times higher for worse standing balance performance (95% CI: 1.06–1.38, p = 0.004). Midlife obesity (BMI ≥ 30 kg/m 2 ), high‐risk WC (≥ 80 cm) and WHR (≥ 0.8) were also associated with a higher prevalence of worse performance on the chair rise and standing balance tests, with PRs from 1.41 to 1.55. No consistent evidence was found for handgrip strength. Conclusions Weight gain from early to mid‐adulthood was associated with worse performance on the chair rise and standing balance tests in midlife, highlighting the potential of early weight‐control strategies to preserve midlife performance.