Associations between physical activity trajectories and cognitive function in women 50 years and older: A nationally representative cohort study from the China Health and Retirement Longitudinal Study

Objective

To examine the longitudinal association between physical activity trajectory changes and cognitive function in women aged 50 years and older.

Methods

Data were obtained from the China Health and Retirement Longitudinal Study, collected between 2011 and 2020, involving 2,760 women aged 50 years and older. Group-based trajectory modeling was used to identify four physical activity trajectory groups: Low-Fluctuation Group, Moderate-Increasing Group, Moderate-Stability Group, and High-Fluctuation Group. Cognitive function was assessed based on episodic memory and mental intactness. Linear mixed-effects models were employed to examine the association between physical activity trajectories and cognitive function, including interaction effects and age-stratified analyses.

Results

The Moderate-Increasing group was significantly associated with higher levels of global cognitive function (β = 0.45, 95% CI: 0.05–0.85) and episodic memory (β = 0.21, 95% CI: 0.05–0.37), particularly among women aged 50–59 years. In contrast, High-Fluctuation and Low-Fluctuation groups exhibited declining trends across cognitive outcomes. Age-stratified analysis suggested that the association between Moderate-Increasing group and cognitive function was not significant among women aged 60 years and older.

Conclusion

In women aged 50–59 years, the Moderate-Increasing group was significantly associated with better global cognitive function and episodic memory; however, this association was attenuated or not observed in older age groups.