Gender-specific association between PM2.5 exposure and cognitive function in middle-aged and elderly Chinese: Evidence from CHARLS

With rapid industrialization and urbanization in China, ambient air pollution—particularly PM_2.5—has become a major public health concern. Existing evidence suggests that chronic exposure to fine particulate matter may contribute to neurodegenerative processes and cognitive decline, yet the sex-specific effects remain underexplored, especially in vulnerable aging populations. This study aimed to assess the gender-specific impact of PM_2.5 exposure intensity and duration on cognitive function in the middle-aged and elderly Chinese population, identify higher risk groups for cognitive impairment, and offer insights into strategies for prevention and early intervention. Integrated datasets from the China Health and Retirement Longitudinal Study (CHARLS) for adults aged 45 to 96 and PM2.5 exposure data from 2001 to 2018 through satellite observations. Cognitive function was evaluated using the CHARLS-HCAP Neurocognitive Test Scale. We employed linear mixed-effects quantile regression models to investigate gender-specific disparities in the association between PM2.5 exposure intensity and duration and cognitive function across diverse cognitive levels. The models were adjusted for demographic, lifestyle, socioeconomic factors, and medical history. Among 17,147 participants contributing 45,242 observations, higher PM2.5 exposure intensity and extended duration were associated with reduced cognitive function in both genders (females: q ≥ 0.66, males: q ≥ 0.96). Notably, these associations were more pronounced among females than males at the same cognition score quantiles. In participants with no or mild cognitive impairment, females exhibited lower cognitive function scores due to higher PM2.5 exposure intensity and prolonged duration (PM2.5 levels ≥ 36 µg/m3) compared to males. These findings indicated differing impacts of PM2.5 exposure on cognitive function relative to gender and cognitive status. These results supported existing evidence of gender-specific differences in the impact of PM2.5 exposure on cognitive decline, identifying females with no or with mild cognitive impairment as the most vulnerable subgroup due to PM2.5 exposure.