Hypocalcemia as biological mechanism responsible for prenatal exposure to polycyclic aromatic hydrocarbons (PAHs) and anemia: Insights from Zunyi birth cohort.

Anemia is still prevalent among low and middle-income countries, posing serious family and social burdens. However, scarce studies provided evidence for real-world exposure to polycyclic aromatic hydrocarbons (PAHs) and anemia among pregnant women, as well as involved biological mechanisms. So, we conducted this study including 1717 late pregnant women from Zunyi Birth Cohort and collected urine samples for PAHs metabolites detection. Logistic regression and restricted cubic spline regression were used to examine exposure-disease risks and dose-response relationships. We conducted Bayesian kernel machine regression, weighted quantile sum regression, and quantile g-computation regression to fit the joint impacts of multiple PAHs in the real-world scenario on hypocalcemia and anemia. Results showed single exposure to 2-OHNap, 2-OHFlu, 9-OHFlu, 1-OHPhe, 2-OHPhe, 3-OHPhe, and 1-OHPyr (all P-trend < 0.05) increased the risks of hypocalcemia and anemia. Moreover, PAHs mixture was significantly related to higher risks of hypocalcemia and anemia, with 3-OHPhe and 1-OHPyr identified as their major drivers, respectively. Importantly, hypocalcemia served as a significant biological mechanism responsible for PAHs and anemia. Our findings suggest that individual and joint exposure to PAHs during late pregnancy elevate the anemia risk, and calcium supplementation might be a low-cost intervention target for reducing the PAHs-related impairment on anemia for pregnant women.