The effect of climate extremes on disability, depression, and cognitive decline in middle-aged and older Chinese adults under different healthy lifestyle

Background: The health risks from climate change are increasing, but the benefits of healthy lifestyles are evident. We aimed to examine the complex relationship between climate change and lifestyles on disability, depression, and cognitive decline in middle-aged and older Chinese adults. Methods: We used a national cohort from the China Health and Retirement Longitudinal Study from 2011-2018 and constructed 27 core extreme climate indices using daily temperature and precipitation. Participants were categorised into the favourable group (4-5 healthy lifestyle factors), the average group (2-3 factors), and the unfavourable group (0-1 factor). The time-dependent Cox regression and linear mixed-effects models were applied to explore associations and further stratified the analysis by lifestyles. Results: A total of 5161 participants were included (19.53% were unfavourable, and 57.70% were average lifestyles). During average 51.76 and 52.79 months follow-up, 1097 of 5161 participants suffered disability, and 1181 developed depression. We observed a significant interaction between lifestyle and specific climate extreme indexes in three outcomes, respectively (all P < 0.05). Compared to the average and favourable lifestyle groups, the corresponding associations for some extreme heat and temperature indexes were more pronounced for disability (all P < 0.05), for some extreme precipitation indexes for depression, and for some extreme heat, cold, and precipitation indexes were much more pronounced (all P < 0.05) for cognitive decline in the unfavourable lifestyle group. Similar associations were found in sensitivity analyses. Conclusions: A healthy lifestyle may attenuate the adverse impacts of frequent climate extremes on disability, depression, and cognitive function among middle-aged and older adults. This study may have important implications for making policies and adaptive strategies to reduce relevant risks to health, especially in low- and middle-income countries.