Maternal exposure to sulfur dioxide and the risk of oral clefts in Liaoning Province, China: a population-based case-control study

Liu, Fang-Hua; Xing, Ze; Gong, Ting-Ting; Zhang, Jia-Yu; Huang, Yan-Hong; Li, Jing; Liu, Shu; Chen, Yan-Ling; Li, Lili; Jiang, Cheng-Zhi; Chen, Zong-Jiao; Zhao, Yu-Hong; Wu, Qi-Jun

Maternal exposure to sulfur dioxide and the risk of oral clefts in Liaoning Province, China: a population-based case-control study

2021

There is limited and equivocal epidemiological evidence relating to the association between maternal sulfur dioxide (SO₂) exposure and the risk of oral clefts (OCs) in offspring. We performed a population-based case-control study in Liaoning province to evaluate aforementioned relationship during 3 months before conception, the first trimester of pregnancy, and their single months. The study involved 3086 patients with OCs and 7950 controls. Data relating to SO₂ concentration was acquired from air monitoring stations throughout the study period. We used a multivariable logistic regression model to evaluate the association between exposure to SO₂ and the risk of OCs during the exposure windows. Maternal SO₂ exposure was positively related to OCs during the 3 months before conception (odds ratio = 1.38, 95% confidence interval: 1.15–1.65; P for trend < 0.01). Positive relationships were obtained from the first and second months before conception and the first month of pregnancy. Thus, our research reflects a relationship between SO₂ exposure and the risk of OCs. Future studies are now required to verify the association between SO₂ exposure and OCs during pregnancy and indicate the most relevant vulnerable exposure time windows.

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