Exposure to ambient ozone and ovarian reserve in Chinese women of reproductive age.

BACKGROUND

Exposure to ambient ozone may be associated with a decline in ovarian reserve; however, epidemiological evidence remains limited. We aimed to estimate the association between ambient ozone exposure and ovarian reserve, and to identify critical exposure windows.

METHODS

We included 2815 women aged 20-45 years who attended an infertility clinic in Chengdu, Sichuan Province, China, between 2014 and 2022. We calculated average concentrations of ozone exposure according to the development of follicles (2-month, 4-month, 6- month) and 1-year period prior to measurement, using a satellite-based spatiotemporal model. Multivariate linear and Poisson regression models were used to assess associations between exposure to ambient ozone and ovarian reserve biomarkers, including antral follicle count (AFC), anti-Müllerian hormone (AMH), and estradiol (E2). Stratified analyses were performed by age, body mass index (BMI), and education to evaluate potential effect modification.

RESULTS

Each 10 μg/m3 increase in ozone concentration during 4-month and 6-month were associated with a 0.88 % (95 % CI: 0.44 %, 1.32 %) and 0.85 % (95 % CI: 0.28 %, 1.43 %) decrease in AFC, respectively. The associations were stronger among women with middle school or lower, and those with BMI ≥24 kg/m2 during both the 4-month and 6-month exposure windows. We observed no associations between exposure to ambient ozone and AMH or E2.

CONCLUSIONS

Exposure to ambient ozone was associated with decreased ovarian reserve among adult women attending an infertility clinic in China. These findings suggest that exposure to ozone could serve as a potential environmental risk factor for diminished ovarian reserve.