Trajectories of Physical Activity and Chronic Conditions Among Mid-Aged Women

INTRODUCTION: Women's physical activity levels vary throughout adulthood. However, the associations between trajectories of physical activity and health outcomes have been little studied. The aim of this study was to examine the associations of physical activity trajectories with incident diabetes, hypertension, obesity, depression, and physical disability in mid-aged women. METHODS: Data were from the 1946-51 cohort of the Australian Longitudinal Study on Women's Health (n=11,611). Mailed surveys at 3-year intervals from 1998 (age 47-52) to 2019 (age 68-73) were used to collect data on physical activity and each outcome. The analyses were conducted in 2023/24. Physical activity trajectories from age 47-61 (2-4 time-points) were identified using group-based trajectory modeling. Cox regression models with time-varying covariates were used to examine the associations of physical activity trajectories with adverse health outcomes onset from ages 56-73 (2-5 time-points). RESULTS: Trajectories of physical activity were labeled as Low (59.7% of participants), Declining (5.9%), Increasing (26.3%), and High (8.1%). The median of 9-year overall physical activity (MET.minutes/week) was 450 in the Low, 1324 in the Declining, 1399 in the Increasing, and 2323 in the High group. Compared with the Low group, the risks of diabetes, obesity and physical disability were lower in the Increasing and High groups, and the risk of depression was lower in the High group. Conversely, the risk of obesity was higher in the Declining group. CONCLUSIONS: Targeting mid-aged women with declining physical activity for prevention programs could enhance health in later life.