Associations between maternal periconceptional exposure to PM2.5 and the risk of cryptorchidism: a case-control study of 4274

Currently, there is limited evidence regarding the association between prenatal exposure to environmental fine particulate matter (PM_2.5) and the occurrence of cryptorchidism. The objective of this study was to evaluate the potential correlation between prenatal exposure to PM_2.5 and the likelihood of cryptorchidism developing in offspring. We performed a 1:1 case-control study, defining the cases as children diagnosed with cryptorchidism at the Children's Hospital Affiliated to Chongqing Medical University from 2013 to 2017, while the control group comprised children born in the corresponding years who did not have any birth defects, chromosomal abnormalities, and had only trauma-related treatments. Between 2012 and 2017, monthly averages of PM_2.5, other pollutants (O₃, PM₁₀) and temperature were gathered based on the geographical coordinates of patients' residences. The study assessed the correlation between the two using multivariate logistic regression model, and sensitivity analysis was conducted to assess the stability of the model. We included a total of 2137 cases and 2137 matched controls from 2013 to 2017. Our findings revealed that there was a positive association between exposure to PM_2.5 during the first 2 months of pregnancy and the occurrence of cryptorchidism. According to this study, the development of cryptorchidism appears to be associated with maternal exposure to PM2.5 during early pregnancy.