Positive change in lifestyle behaviors improve cognitive health in older adults: a 10-year cohort study

Global burden of cognitive decline is rapidly increasing, yet existing research on modifiable lifestyle factors often relies on static assessments. To address this gap, this study aims to explore the dynamic, joint trajectories of multiple lifestyle behaviors and their association with cognitive health in older adults.

This study included 6765 older adults from the Chinese Longitudinal Healthy Longevity Survey. Data on lifestyle, including dietary habits, sleep quality, physical, cognitive, and social activity were self-reported from 2008 to 2014. Cognitive function was measured using the Mini-Mental State Examination from 2014 to 2018. To capture the joint trajectories of these lifestyle behaviors over time, parallel-process latent class growth analysis was used. The identified behavioral trajectory classes were subsequently examined for their associations with cognitive outcomes using cox regression models and linear mixed effects models.

Over a mean follow-up period of 5.9 years, 1659 participants (24.5%) developed cognitive impairment. Three distinct lifestyle behavior trajectory classes were identified: "Low- Declining" (n = 4342, 64.2%), "Moderate-Improving" (n = 1777, 26.3%), and "High-Declining" (n = 646, 9.5%). Compared with the Low- Declining group, the Moderate-Improving group was associated with a lower risk of cognitive impairment (HR = 0.368, 95% CI: 0.269-0.396), a longer time to cognitive impairment onset (mean = 6.433 years) and a slower rate of annual cognitive decline (0.806 points per year). Similarly, the High-Declining group showed a reduced risk (HR = 0.629, 95% CI: 0.507-0.779), delayed onset (mean = 4.969 years) and a slower decline rate (0.543 points per year) compared with the Low- Declining group.

An upward trajectory of moderate lifestyle engagement, as well as a high but declining class, was associated with better cognitive outcomes compared with persistently low or declining engagement. These findings highlight that the direction of lifestyle change, rather than intensity alone, may be critical for cognitive health, supporting preventive strategies that emphasize gradual and sustainable improvements in lifestyle behaviors.