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Abstract

Background/aims: In postmenopausal females, hormone replacement therapy (HRT) may have positive effect on body composition, physical function, and metabolic health, and the impact of modifiable health behaviors (MHBs) may vary across menopausal and HRT status. This study aimed to characterize longitudinal changes in relationships between MHBs and health outcomes in relation to menopausal and HRT status. Methods: Baseline and first follow-up data from the Canadian Longitudinal Study on Aging were used. Participants were categorized into 4 different groups including pre/peri-menopausal, postmenopausal-HRT naïve, postmenopausal-current HRT users, and postmenopausal-previous HRT users. MHBs included diet quality (PURE diet score), total physical activity, and sleep duration. Health outcomes included fat and appendicular lean mass index, gait speed, maximal grip strength, and metabolic health z-score. Analysis of covariance and linear mixed models were used with age and demographic measurements as covariates. Results: Among 10,165 females, mean age was 61.3 ± 9.9 years, and 67.6% were postmenopausal. At baseline, PURE diet score and physical activity were negatively associated with fat mass index and positively associated with appendicular lean mass index, gait speed, and grip strength. No association was observed for sleep duration. After three years of follow-up, higher PURE diet score and physical activity were increasingly associated with improved metabolic health z-score. The effect of sleep duration on body composition was stronger, and on physical function was weaker over time. The relationship between physical activity and fat mass index was stronger over time especially in all postmenopausal groups, and the relationship between sleep duration and appendicular lean mass index was stronger in the postmenopausal-HRT naïve group. The relationship between sleep duration, gait speed, and grip strength were weaker in postmenopausal-current HRT users. Conclusion: At baseline, higher PURE diet scores and physical activity were related to lower fat mass, greater appendicular lean mass, and better physical function. Over time, diet and physical activity became more strongly linked to improved metabolic health, and sleep duration showed increasing associations with body composition, particularly among postmenopausal females not using HRT. Associations between sleep and physical function measures weakened over time, with notable differences by menopausal and HRT status.