Fine particulate matter components and reproductive hormones in female adults: A 15-year longitudinal cohort study

Abstract

Background

Few cohort studies have evaluated the long-term impacts of ambient fine particulate matter (PM_2.5) and its components on reproductive hormone levels in female adults.

Methods

We conducted a 15-year retrospective cohort study in Taiwan between 2003 and 2017. The two-year average concentrations of PM_2.5 and its components, including sulfate (${SO}_4^{2-}$), nitrate (${NO}_3^{-}$), ammonium (${NH}_4^{+}$), organic matter (OM), and black carbon (BC), were assessed at each participant's addresses. Linear mixed models were used to examine the associations of PM_2.5 and its components with reproductive hormones, including follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone (T), estradiol (E2), and prolactin (PRL). Stratified analyses were conducted to identify vulnerable populations.

Results

17,152 female adults were included. Each interquartile range (IQR: 3.545 μg/m³) increase in PM_2.5 was associated with a 0.585 mIU/mL [95% confidence interval (CI): 0.190–0.980] increase in FSH levels. Among the five components of PM_2.5, BC had the strongest positive association [each IQR (0.272 μg/m³) increase was associated with a 0.863 mIU/mL (95% CI: 0.476–1.250) increase in FSH levels], followed by OM, ${SO}_4^{2-}$, and ${NH}_4^{+}$. Similar associations were found for LH, with a 0.483 mIU/mL (95% CI: 0.225–0.742) and 0.684 mIU/mL (95% CI: 0.431–0.938) increase in LH levels per IQR increase in PM_2.5 and BC, respectively. The pollutants were marginally associated with decreased E2 levels and increased PRL levels. Non-linear associations between PM_2.5 and its components and the levels of FSH, LH, E2, and PRL were observed. These pollutants were also positively associated with T levels among young adults. Post-menopausal women were more susceptible to the chronic impacts of PM_2.5 and its components.

Conclusion

Our study highlighted the adverse impacts of long-term exposure to PM_2.5 components on hormonal homeostasis, revealing the biological mechanism of air pollution-reproductive health associations in females. Implementing stringent control of air pollution levels can benefit reproductive health in female adults, even in moderately polluted regions.