Effects of Prenatal Exposure to Ozone, Heatwave and Green Space on Neonatal Congenital Heart Disease: A Case-Control Study in Eastern China

Congenital heart disease (CHD) is the most prevalent birth defect. Ozone and heatwave exposure during pregnancy could increase the risk of adverse birth outcomes. Green space might be associated with beneficial birth outcomes. The research on the combined effects of those exposures on CHD is limited. Therefore, we conducted a multicenter case-control study based on a surveillance system in Zhejiang Province, China, to explore the effect of ozone, heatwave, and green space exposure during early pregnancy on CHD and their interaction. The inverse distance weighting method and normalized difference vegetation index were applied to assess maternal ozone and green space exposure, respectively. The heatwave definition is from the National Oceanic and Atmospheric Administration. Our study reveals positive associations of heatwave and ozone exposure with CHD (ozone: OR = 1.07, 95% CI: 1.02, 1.13; heatwave: OR = 1.29, 95% CI: 1.18, 1.40), and green space in different buffers around residence exerted protective effects on CHD, with ORs ranging from 0.93 to 0.94. Associations between ozone and CHD were weakened among participants with higher NDVI. Ozone's effects on CHD were stronger with the increased duration of heatwave exposure. Our study indicates that ozone and heatwave exposure could increase the risk of CHD, and high green space is a protective factor for CHD. Meanwhile, high green space exposure could attenuate the effect of ozone on CHD, but heatwave exposure strengthened it.