Associating ambient exposure to fine particles and human fertility rates in China

Background: Adverse effects of ambient fine particles (PM2.5) on sperm quality and oocyte fertilization have been identified by previous research. However, insufficient human studies tested associations between PM2.5 and decreased fertility rates. Methods: We associated long-term exposure to PM2.5 and county-level fertility rates reported by 2010 census across China. Exposure assessments were based on PM2.5 maps (2009-2010) with a spatial resolution of 0.1 degrees derived from satellite remote sensing data from another published study. We used a Poisson regression to examine the relationship between PM2.5 and fertility rates with adjustment of potential confounders including county-level socioeconomic factors (e.g. sex ratio) and a spatially smoothed trend. Results: We found that fertility rates were significantly decreased by 2.0% (95% confidence interval: 1.8%, 2.1%) per 10 mu g/m(3) increment of PM2.5. We also found a geographical variation of the associations. Conclusions: The study add to epidemiological evidences on adverse effects of PM2.5 on fertility rates. (C) 2018 Elsevier Ltd. All rights reserved.