International studies of prenatal exposure to polycyclic aromatic hydrocarbons and fetal growth

Abstract

Objectives: Polycyclic aromatic hydrocarbons (PAHs) are ubiquitously distributed human mutagens and carcinogens. However, lack of adequate air monitoring data has limited understanding of the effects of airborne PAHs on fetal growth. To address this gap in knowledge, we examined the association between prenatal exposure to airborne PAHs and birth weight, birth length, and birth head circumference, respectively, in Krakow, Poland, and New York City (NYC).

Methods: The parallel prospective cohort studies enrolled nonsmoking, healthy, and nonoccupationally exposed women and their newborns. Personal air monitoring of pregnant women was conducted over 48 hr. To control for maternal environmental tobacco smoke (ETS) exposure, we excluded those with umbilical cord plasma cotinine concentrations > 25 ng/mL. Mean cord plasma cotinine concentrations in both ethnic groups were <or= 0.5 ng/mL.

Results: Prenatal PAH exposure was 10-fold higher in Krakow than in NYC. Prenatal PAH exposure was associated with significantly reduced birth weight in both Krakow Caucasians (p < 0.01) and in NYC African Americans (p < 0.01), controlling for known and potential confounders, but not in NYC Dominicans. Within the lower exposure range common to the two cities (1.80-36.47 ng/m3), the effect per unit PAH exposure on birth weight was 6-fold greater for NYC African Americans than for Krakow Caucasians (p = 0.01).

Conclusions: These results confirm the adverse reproductive effect of relatively low PAH concentrations in two populations and suggest increased susceptibility of NYC African Americans. Fetal growth impairment has been linked to child developmental and health problems. Thus, substantial health benefits would result from global reduction of PAH emissions.

Figure 1

Adjusted scatterplots of birth weight (BW) (A), length (BL) (B), and head circumference (BHC) (C) versus (ln)∑8 c-PAHs, restricted to 1.80–36.47 ng/m³ range. The scatterplot was based on the combined multivariate model shown in Table S3(B) (Supplemental Material). The regression lines represent the slopes of the association for the two ethnic groups (123 NYC African Americans and 227 Krakow Caucasians). The scatterplot for NYC Dominicans is not shown because the PAHs had no significant effect on any of the birth outcomes.