The relationship between prenatal exposure to airborne polycyclic aromatic hydrocarbons (PAHs) and PAH–DNA adducts in cord blood

Abstract

In a birth cohort study, we have assessed the dose-response relationship between individual measurements of prenatal airborne polycyclic aromatic hydrocarbon (PAH) exposure and specific PAH-DNA adducts in cord blood adjusted for maternal blood adducts and season of birth. The study uses data from an earlier established birth cohort of children in Krakow. The final analysis included 362 pregnant women who gave birth to term babies and had complete data on personal exposure in the second trimester of pregnancy to eight airborne PAHs including benzo[a]pyrene (B[a]P), as well as DNA adducts, both in maternal and cord blood. The relation between cord blood PAH-DNA adducts and airborne prenatal PAH exposure was non-linear. Although cord blood PAH-DNA adducts were significantly associated with the B[a]P exposure categorized by tertiles (non-parametric trend z=3.50, P<0.001), the relationship between B[a]P and maternal blood adducts was insignificant (z=1.63, P=0.103). Based on the multivariable linear regression model, we estimated the effect of the prenatal airborne B[a]P on the level of cord blood adducts. In total, 14.8% of cord blood adducts variance was attributed to the level of maternal adducts and 3% to a higher prenatal B[a] exposure above 5.70 ng/m(3). The calculated fetal/maternal blood adduct ratio (FMR) linearly increased with B[a]P exposure (z=1.99, P=0.047) and was highest at B[a]P concentrations exceeding 5.70 ng/m(3). In conclusion, the results support other findings that transplacental exposure to B[a]P from maternal inhalation produces DNA damage in the developing fetus. It also confirms the heightened fetal susceptibility to prenatal PAH exposure that should be a matter of public health concern, particularly in the highly polluted areas, because DNA adducts represent a pro-carcinogenic alteration in DNA. The continuation of this birth cohort study will assess the possible health effects of fetal DNA damage on the health of children and help in establishing new protective guidelines for newborns.