Industrial Air Pollution Leads to Adverse Birth Outcomes: A Systematized Review of Different Exposure Metrics and Health Effects in Newborns

Dietary Polycyclic Aromatic Hydrocarbon (PAH) Consumption and Risk of Adverse Birth Outcomes: A Systematic Review and Meta-Analysis

BACKGROUND

There is suggestive epidemiological evidence that maternal dietary polycyclic aromatic hydrocarbons (PAH) may increase the risk of adverse birth outcomes. We sought to summarize the available evidence on the effect of dietary PAH exposure on birth outcomes.

METHODS

PubMed and Scopus databases were systematically searched from inception up to November 2022. Studies were included if they were original articles, were conducted in a human population, assessed dietary PAH consumption, and investigated the relationship between dietary PAH consumption and any adverse birth outcomes. Risk of bias in the included studies was assessed qualitatively and quantitatively. A random effects model was used to compute summary effect estimates in the meta-analysis.

RESULTS

Six observational studies (five prospective cohort studies, and one prevalence case-control study) were included. The included studies assessed dietary PAH exposure using dietary questionnaires. Information on the outcomes of interest was obtained from medical records. Three of the included studies were rated as good quality with the remaining three studies rated as fair quality. One study was considered as having low risk of bias for selection, information and confounding bias. Dietary PAH consumption was associated with 5.65 g [95% confidence interval (CI): - 16.36 , 5.06] and 0.04 cm   (95% CI: - 0.08 , 0.01) reductions in birth weight and birth length, respectively, and an increase in head circumference [effect size  ( ES ) = 0.001 ; 95% CI: - 0.003 , 0.005]. The CI of all the summary effect estimates, however, included the null value. In the sensitivity analysis that included only studies that assessed dietary PAH exposure as the primary exposure of interest, dietary PAH consumption was associated with much higher reductions in birth weight (ES = - 14.61 ; 95% CI: - 21.07 , - 8.15 ) and birth length (ES = - 0.06 ; 95% CI: - 0.1 , - 0.03 ). High statistical heterogeneity was observed in the birth weight and birth length analysis and in the head circumference sensitivity analysis.

DISCUSSION

The body of epidemiological evidence suggests that maternal dietary PAH exposure is associated with reduced fetal growth, measured as birth weight and length. There was considerable heterogeneity in the measurement of PAH exposure among the included studies. Also, nonstandardized and validated dietary questionnaires were employed by a majority of the included studies with potential exposure misclassification. These issues are likely to impact the summary effect estimates computed and underscores the need for high-quality epidemiological studies with improved exposure assessment and adequate confounding control to strengthen the evidence base. https://doi.org/10.1289/EHP12922.

Perinatal Health Inequalities in the Industrial Region of Estonia: A Birth Registry-Based Study

Despite the increasing number of studies on industrially contaminated sites (ICS) and their health effects, there are very few studies on perinatal health outcomes in ICSs. In the present study, we examined the perinatal health inequalities by comparing adverse birth outcomes (ABOs) in the oil shale industry region of Ida-Viru County in Estonia with national-level figures and investigated the effects of maternal environmental and sociodemographic factors. Based on the 208,313 birth records from 2004-2018, Ida-Viru ICS has a birth weight 124.5 g lower than the average of 3544 g in Estonia. A higher prevalence of preterm birth (4.3%) and low birth weight (4.8%) in Ida-Viru ICS is found compared to 3.3% on both indicators at the national level. Multiple logistic regression analysis shows the statistically significant association of ABOs with fine particle (PM_2.5) air pollution, mother's ethnicity, and education throughout Estonia. However, in Ida-Viru ICS, the ABOs odds are remarkably higher in these characteristics except for the mother's ethnicity. Furthermore, the ABOs are associated with the residential proximity to ICS. Thus, the Ida-Viru ICS has unequally higher odds of adverse perinatal health across the environmental and sociodemographic factors. In addition to reducing the air pollutants, policy actions on social disparities are vital to address the country's unjustly higher perinatal health inequalities, especially in the Ida-Viru ICS.