The association between ambient air pollution and birth defects in five major ethnic groups in Liuzhou, China

Abstract

Background Studies suggest that exposure to ambient air pollution during pregnancy may be associated with increased risks of birth defects (BDs), but conclusions have been inconsistent. This study describes the ethnic distribution of major BDs and examines the relationship between air pollution and BDs among different ethnic groups in Liuzhou city, China. Methods Surveillance data of infants born in 114 registered hospitals in Liuzhou in 2019 were analyzed to determine the epidemiology of BDs across five major ethnic groups. Concentrations of six air pollutants (PM2.5, PM10, SO2, CO, NO2, O3) were obtained from the Liuzhou Environmental Protection Bureau. Logistic regression was used to examine the associations between ambient air pollution exposure and risk of BDs. Results Among 32,549 infants, 635 infants had BDs, yielding a prevalence of 19.5 per 1000 perinatal infants. Dong ethnic group had the highest prevalence of BDs (2.59%), followed by Yao (2.57%), Miao (2.35%), Zhuang (2.07%), and Han (1.75%). Relative to the Han ethnic group, infants from Zhuang, Miao, Yao and Dong groups had lower risks of congenital heart disease, polydactyly, and hypospadias. The Zhuang ethnic group had higher risks of severe thalassemia, cleft lip and/or palate, and syndactyls. Overall BDs were positively correlated with air pollutants PM10 (aOR =1.14, 95% CI:1.12 ~ 2.43; aOR =1.51, 95% CI:1.13 ~ 2.03 for per 10μg/mg3 increment) and CO (aOR =1.36, 95% CI:1.14 ~ 2.48; aOR =1.75, 95% CI:1.02 ~ 3.61 for every 1 mg /m3 increment) in second and third month of pregnancy. SO2 was also significantly associated with BDs in the second month before the pregnancy (aOR = 1.31; 95% CI: 1.20 ~ 3.22) and third month of pregnancy (aOR =1.75; 95% CI:1.02 ~ 3.61). Congenital heart disease, polydactyl, cleft lip and/or palate were also significantly associated with PM10, SO2 and CO exposures. However, no significant association was found between birth defects and O3, PM2.5 and NO2 exposures (P > 0.05). Conclusion This study provides a comprehensive description of ethnic differences in BDs in Southwest China and broadens the evidence of the association between air pollution exposure during gestation and BDs.

First trimester exposure to ambient gaseous air pollutants and risk of orofacial clefts: a case–control study in Changsha, China

“…In the single pollutant analysis of NO 2 , we observed increases of 35–61% in the risk of CL/P, as well as increases of 60–66% in the risk of CPO per IQR increase in NO 2 in all months of the first trimester of pregnancy. Our estimates supported the results from the studies performed by Zhu et al in the U.S. [ 11 ] and Wang et al in China [ 18 ], which reported an aOR of 3.64 (95% CI 1.73, 7.66) for CPO per IQR increase during weeks 3–8 of pregnancy and a RR of 1.19 (95% CI 1.03, 1.36) for cleft palate per 10 μg/m 3 increase during the first trimester of pregnancy, respectively. No other previous studies that estimated the effect of NO 2 found significant results [ 18 , 26 , 28 ].…”

“…For instance, a case–control study including 653 cases from Taiwan, China reported the risk of CL/P was increased in relation to O 3 levels in the first (aOR = 1.20, 95% CI 1.02, 1.39) and the second month of pregnancy (aOR = 1.25, 95% CI 1.03, 1.52) [ 6 ], Another cohort study performed by Zhao et alin Wuhan, China announced significant associations for CPO in the second and the third month of pregnancy, with aORs of 1.21 (95% CI 1.03, 1.42) and 1.18 (95% CI 1.02, 1.37), respectively [ 15 ]. Unfortunately, we failed to detect a positive effect of O 3 on CL/P or CPO in Changsha, China in this study, as did most of the previous studies [ 10 , 12 , 18 ].…”

“…Meanwhile, the largest developing country in the world has been confronted with increasing challenges in environmental protection [ 14 ], and the health effects of gaseous air pollutants, which originate from massive combustion of various fuels, are one of the greatest concerns. Based on our review of existing literature, however, only a few studies have explored the effects of exposure to gaseous air pollutants on orofacial clefts in China, but have reported inconsistent results [ 15 – 18 ]. Of these studies, two used single-pollutant model without adjustment for the coexisting pollutants, thus failed to isolate the independent role of gaseous air pollutants [ 15 , 16 ].…”

Birth defects data from hospital-based birth defect surveillance in Guilin, China, 2018–2020

“…In this hospital-based study, we used Guilin City's perinatal BD monitoring data to describe the epidemiological characteristics of common BDs and review the etiological identification of these BDs in Guilin, Guangxi province, China. The total prevalence of BDs was 13.55 per 1,000 births from 2018 to 2020, which was lower than the prevalence rate of 19.53 per 1,000 births in Liuzhou, another city in Guangxi ( 20 ).…”

Maternal exposure to ambient air pollution and risk of congenital heart defects in Suzhou, China

“…Finally, although several relevant covariates were controlled for in this study, we cannot eliminate the possibility of residual confounding from other factors, such as e genetic problems of parents and fetal, maternal complications, passive smoking, and time spent outdoors. Maternal smoking and alcohol use were not controlled for because < 0.3% of the mothers during pregnancy reported smoking or drinking alcohol ( 22 ).…”