Effects of Air Pollution on the Risk of Congenital Anomalies: A Systematic Review and Meta-Analysis

Abstract

Congenital anomalies are the main causes of preterm and neonatal mortality and morbidity. We investigated the association between congenital anomalies and mothers’ exposure to air pollution during pregnancy by combining risk estimates for a variety of air pollutants (SO2, NO2, PM10, PM2.5, CO and O3) and anomaly defect outcomes. Seventeen articles were included in the systematic review and thirteen studies were taken into account in the meta-analysis. Combined estimated were calculated separately according to whether the exposure metric was continuous or categorical. Only one significant combination was; NO2 concentrations were significantly associated with coarctation of the aorta (OR = 1.20 per 10 ppb, 95% CI, (1.02, 1.41)). This finding could stem from strong heterogeneity in study designs. Improved exposure assessment methods, in particular more accurate spatial measurements or modeling, standardized definition of cases and of better control of confounders are highly recommended for future congenital anomalies research in this area.

Air Pollution and the Risk of Birth Defects in Anqing City, China

“…6 And another systematic review and meta-analysis indicated that OR of NO 2 (per 10 ppb NO 2 ) exposure was 1.20 (95% CI 1.02 to 1.41). 5 In addition, one study in Haikou city of China investigated that the adjusted OR for PM 10 was 1.039 (95% CI 1.016 to 1.063) and 1.066 (95% CI 1.043 to 1.090) in the second and third month pregnancy, respectively. 24 Kim et al 25 reported an increased risk for all categories of birth defects related to gestational PM 10 exposure (OR ¼ 1.16, 95% CI 1.00 to 1.34).…”

“…4 European Surveillance of Congenital Anomalies records showed the perinatal death rate of 9.3 per 10,000 births of all congenital anomalies from 2008 to 2012. 5 Major structural birth defects are diagnosed in 2% to 4% of births. 6 The etiologies remain unclear for about half of these defects.…”

Association between benzene and congenital anomalies in Oklahoma, 1997–2009

“…The authors observed no association with oral clefts for any of the pollutants evaluated. However, in an updated meta-analysis including these studies, Chen et al 30 observed only one statistically significant finding between NO 2 and coarctation of the aorta (combined OR 1.20, 95% CI 1.02 to 1.41), with the association between O 3 and cleft lip approaching significance (combined OR 1.17, 95% CI 0.98 to 1.41). Air pollution is complex to study due to the multiple types of air pollutants, which are frequently co-linear, and multiple methods of measuring air pollutants, which include using air monitoring stations and model-based estimates 31 32.…”

A perspective on the developmental toxicity of inhaled nanoparticles

“…Currently, there is strongest evidence regarding maternal exposure to PM and other atmospheric pollutants for cardiac congenital malformations such as atrial septal defects [170]. A more recent meta-analysis observed significant associations only between NO 2 concentrations (and not particles) in air and coarctation of the aorta [171].…”