Bin Tang

Purpose: Healthy lifestyle is considered a modifiable factor related to cognitive health, while evidence from multi-ethnic regions remains scarce. This study aimed to examine the association between healthy lifestyle and cognitive function among middle-aged and older adults in ethnically diverse communities and to explore heterogeneity across population characteristics. Methods: This cross-sectional study was conducted in Yunnan Province, China from July to December 2022. Cognitive function was assessed using the Brief Community Screening Instrument for Dementia (BCSI-D). Healthy lifestyle scores were constructed based on seven behaviors: smoking status, alcohol consumption, physical activity, social contact, sleep duration, physical examination and body mass index (BMI) categories. Each behavior was assigned 1 point if the participant met the healthy criteria and 0 otherwise. Participants were categorized into favourable, intermediate, and unfavourable lifestyle groups according to the final score. Chi-square tests were used to compare cognitive function status across population characteristics, and Kruskal–Wallis tests were used to compare BCSI-D scores across lifestyle groups within each subgroup. Logistic regression models and subgroup analyses were conducted to examine the lifestyle-cognition association, with formal interaction tests performed to assess effect modification across subgroups. A sensitivity analysis was additionally conducted using the healthy lifestyle score as a continuous variable. Results: Out of the total 2708 participants, approximately 68.76% were classified in the favourable lifestyle category. Across nearly all characteristics, the unfavourable lifestyle category consistently showed the lowest mean BCSI-D scores. An unhealthy lifestyle was significantly associated with higher odds of cognitive impairment in the overall population (OR= 1.272, 95% CI:1.012– 1.598). Subgroup analyses further revealed apparent heterogeneity, with the associations observed among two key populations: participants aged 60– 74 years (OR= 1.486, 95% CI:1.066– 2.070) and those from Zhiguo ethnic minority groups (OR= 1.570, 95% CI:1.132– 2.178). Significant associations were also observed among married (OR= 1.366, 95% CI:1.046– 1.784), educated (OR= 1.562, 95% CI:1.106– 2.204), monthly household income of 1000– 2999 Chinese Yuan (OR= 1.582, 95% CI:1.057– 2.367) and without ADL impairment (OR= 1.498, 95% CI:1.074– 2.088) individuals. However, formal interaction testing confirmed statistically significant effect modification only for education level (P =0.036), while no significant interactions were observed for the remaining characteristics. Conclusion: This study suggests that a healthy lifestyle was associated with better cognitive outcomes among middle-aged and older adults in this resource-limited, multi-ethnic population. The association was observed in certain population groups, although this potential heterogeneity warrants further confirmation. These findings highlight that culturally tailored lifestyle interventions may offer a feasible strategy to reduce cognitive health disparities in diverse settings.