Association of ambient PM2.5 and its components with preeclampsia risk among pregnant women in a high-altitude region.

The associations between ambient fine particulate matter (PM2.5) and its components (sulfate, ammonium, nitrate, organic matter, and black carbon) and the risk of preeclampsia remain unclear, particularly in high-altitude regions where evidence is limited. This study aimed to provide novel insights into this issue. Lanzhou, China, was selected as a representative high-altitude city, and data from 169,484 women who delivered between 2016 and 2021 were included. Logistic regression models were used to evaluate the associations between individual exposure to PM2.5 and its components and the risk of preeclampsia. The joint associations and the contribution weights of each component were further assessed using quantile g-computation. Additionally, distributed lag nonlinear models were applied to identify potential lagged associations. The results indicated that individual exposures to PM2.5 and its components during the entire exposure period, the preconception period, and the first trimester were significantly associated with an increased risk of preeclampsia (p < 0.05). Mixed exposures to PM2.5 components during the entire exposure period and the preconception period were also significantly associated with an increased risk of preeclampsia (p < 0.05), with black carbon (0.43) and ammonium (0.48) showing the highest positive weights, respectively. The strongest associations between high-level pollutant exposure and preeclampsia risk were observed during the preconception period or the first trimester. These findings suggest that public health interventions should target key PM2.5 components and critical exposure windows to mitigate the risk of preeclampsia in high-altitude regions.