PT  - JOURNAL ARTICLE
AU  - Fang-Hua Liu
AU  - Hui-Xu Dai
AU  - Ting-Ting Gong
AU  - Jia-Yu Zhang
AU  - Jing Li
AU  - Zong-Jiao Chen
AU  - Li-Li Li
AU  - Yan-Ling Chen
AU  - Shu Liu
AU  - Cheng-Zhi Jiang
AU  - Yan-Hong Huang
AU  - Yu-Hong Zhao
AU  - Qi-Jun Wu
TI  - Maternal preconception and first trimester exposure to PM<sub>10</sub> and the risk of oral clefts in offspring: a population-based, case–control study
AID  - 10.1136/oemed-2020-106434
DP  - 2020 Jul 31
TA  - Occupational and Environmental Medicine
PG  - oemed-2020-106434
4099  - http://oem.bmj.com/content/early/2020/07/31/oemed-2020-106434.short
4100  - http://oem.bmj.com/content/early/2020/07/31/oemed-2020-106434.full
AB  - Background Current literature describes limited and controversial evidence on the associations between maternal preconception and first trimester exposure to particulate matter with a diameter ≤10 µm (PM10) and the risk of oral cleft (OC).Methods We conducted a case–control study involving 3086 OC cases and 7950 controls, registered in the Maternal and Child Health Certificate Registry in Liaoning Province between 2010 and 2015. PM10 concentrations were obtained from the Environment Protection Bureau. The exposure windows included the 3 months before pregnancy, the first trimester and the individual months. Unconditional logistic regression model was performed to estimate the OR and 95% CI for the association between PM10 exposure and the risk of OC, cleft lip only (CLO), cleft palate only (CPO), and cleft lip and palate (CLP).Results Maternal PM10 exposure was positively associated with an increased risk for OC during the 3 months preconception (per 10 µg/m3 increment: OR=1.04, 95% CI 1.01 to 1.07; highest vs lowest quartile: OR=1.23, 95% CI 1.04 to 1.45) and the first trimester (per 10 µg/m3 increment: OR=1.05, 95% CI 1.02 to 1.08; highest vs lowest quartile: OR=1.37, 95% CI 1.15 to 1.64). Analyses based on individual months presented similar positive associations, particularly in the second month of pregnancy (OR=1.77, 95% CI 1.51 to 2.09) for highest versus lowest quartile. In the subtype analysis, stronger associations were observed for CLO, whereas there was negligible evidence for CPO and CLP. Sensitivity analyses using propensity score matching generated similar findings.Conclusions Our study provides evidence that PM10 exposure during the 3 months preconception and the first trimester increases the risk of OC.