Association between air pollution and climate parameters exposure during the periconceptional period and hypospadias risk in Turkish offspring: A case-control study

We aimed to investigate the associations between hypospadias and contact to air pollutants and climate parameters during the pre- and post-conceptional periods. This study has been carried out as a multicentre case-control study involving 340 children with hypospadias between the ages of 0–3 years and 357 children in the same age range who applied for circumcision. A total of 7 air pollutant (PM_2.5, PM₁₀, NO, NO₂, SO₂, CO, O₃), 5 climate parameters [air temperature, relative humidity (RH), air pressure (AP), wind speed (WS) and precipitation amounts data were obtained. In the multivariate logistic regression analysis, younger maternal age (reference: >35 years) and maternal smoking (reference: no exposure) were significantly associated with a higher likelihood of hypospadias. Conversely, folic acid supplementation intake during pregnancy (reference: no supplementation) and maternal BMI in the range of 25–30 (reference: <25) were associated with a lower likelihood of its occurrence. After adjusting for child-family characteristics, increased interquartile ranges (IQR) of CO, mean temperature, minimum temperature, RH, and AP were positively associated with hypospadias, whereas SO₂ levels and diurnal temperature range (DTR) were inversely associated. Comprehensive analysis of individual and environmental factors further highlighted that younger maternal age, smoking exposure, PM₁₀, and air pressure were positively associated with hypospadias, while a greater DTR was inversely associated. Younger maternal age, smoking exposure, and specific air pollutants, such as PM₁₀ and CO, as well as climatic factors like AP, were positively associated with hypospadias. These findings underscore the importance of mitigating environmental exposures and promoting maternal health interventions to reduce the risk of congenital anomalies like hypospadias. Further longitudinal studies are warranted to confirm these associations and explore underlying mechanisms.