The impact of living environmental factors on cognitive function and mild cognitive impairment: evidence from the Chinese elderly population

Mild cognitive impairment represents a pivotal stage in the cognitive decline of older adults, with a considerable risk of advancing to dementia. Recognizing how living environmental factors affect cognition is crucial for crafting effective prevention and intervention strategies. This study seeks to elucidate the relationship between various living environmental factors and cognitive function, with a specific focus on mild cognitive impairment, within a Chinese elderly population. This is a cross-section and longitudinal study. Utilizing data from CHARLS, our cross-sectional analysis included 4,401 participants, while the cohort study comprised 3,177 individuals. We assessed living environmental factors based on household fuel types, water sources, indoor temperatures, residential building types, and ambient PM2.5 levels. We employed multiple linear regression for cross-sectional analyses and Cox proportional hazards regression models for longitudinal assessments to determine the effects of living environments on cognitive function and MCI risk. Stratified analyses, interaction tests, and sensitivity analyses were conducted to further validate our findings. The findings revealed that, compared to those in high-risk environments, participants in low-risk settings exhibited higher cognitive scores (β = 1.25, 95%CI: 0.85, 1.65), better mental status (β = 0.70, 95%CI: 0.48, 0.92), and improved episodic memory (β = 0.27, 95%CI: 0.13, 0.41). Over a 7-year follow-up, the use of low-risk living environments (HR = 0.67, 95%CI: 0.49, 0.91), including clean fuels (HR = 0.74, 95%CI: 0.57, 0.95) and tap water (HR = 0.84, 95%CI: 0.71, 1.00), demonstrated a protective effect against MCI development. This correlation remained significant regardless of age, gender, residence, education level, smoking, alcohol consumption, and depression. This research provides substantial evidence that living environmental factors significantly affect cognitive function and MCI risk in Chinese older adults. Enhancing living conditions may be a key strategy for promoting cognitive health and preventing MCI in this demographic. Further research is necessary to explore the long-term impacts and potential intervention strategies to optimize living environments for better cognitive outcomes in aging populations.