title: Prenatal exposure to polycyclic aromatic hydrocarbons and cognitive dysfunction in children.
abstract: Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental pollutants produced by combustion of fossil fuel and other organic materials. Both experimental animal and human studies have reported the harmful impacts of PAH compounds on fetal growth and neurodevelopment, including verbal IQ of children. Here, we have assessed the association between cognitive function of children and prenatal PAH exposures. The study is part of an ongoing, longitudinal investigation of the health effects of prenatal exposure to air pollution on infants and children in Krakow, Poland. The subjects in this report included 170 children whose mothers were enrolled to the study in the first or second trimester of pregnancy whose cord blood were tested for PAH-DNA adducts and who were assessed at age 7 using the Wechsler Intelligence Scale for Children-Revised (WISC-R). The outcome of a priori interest was depressed verbal IQ index (DepVIQ), which is the difference between WISC-R performance and verbal IQ scores. Prenatal PAH exposure was measured by cord blood PAH-DNA adducts, an individual dosimeter, integrating exposure from various sources of exposure over the gestational period. The estimated effect of prenatal PAH exposure on cognitive function was adjusted in multivariable regression for a set of potential confounders (child's gender, parity, maternal education, breastfeeding practice, environmental tobacco smoke (ETS), and postnatal PAH exposure). The prevalence of DepVIQ was significantly higher in children with detectable PAH-DNA adducts compared to those with undetectable adducts (13.7 vs. 4.4 %,). Binary multivariable regression documented that the relative risk of DepVIQ increased threefold with a ln-unit increase in cord blood adducts (relative risk (RR) = 3.0, 95 % confidence interval (CI) 1.3-6.8). Postnatal PAH exposure also increased the risk of DepVIQ (RR = 1.6, 95 % CI 1.1-2.5). Long-term exclusive breastfeeding (at least 6 months) showed a protective effect (RR = 0.3, 95 % CI 0.1-0.9). In conclusion, these results provide further evidence that PAHs are harmful to the developing fetal brain with effects extending through childhood, with implications for the academic success of the children.
authors.affiliation: Chair of Epidemiology and Preventive Medicine, Jagiellonian University Medical College, 7, Kopernika Street, Krakow, Poland, myjedryc@cyf-kr.edu.pl.
authors.forename: Wiesław A
authors.initials: WA
authors.lastname: Jedrychowski
authors.forename: Frederica P
authors.initials: FP
authors.lastname: Perera
authors.forename: David
authors.initials: D
authors.lastname: Camann
authors.forename: John
authors.initials: J
authors.lastname: Spengler
authors.forename: Maria
authors.initials: M
authors.lastname: Butscher
authors.forename: Elzbieta
authors.initials: E
authors.lastname: Mroz
authors.forename: Renata
authors.initials: R
authors.lastname: Majewska
authors.forename: Elżbieta
authors.initials: E
authors.lastname: Flak
authors.forename: Ryszard
authors.initials: R
authors.lastname: Jacek
authors.forename: Agata
authors.initials: A
authors.lastname: Sowa
mesh_terms: D000393:Air Pollutants / Q000032:analysis / Q000633:toxicity*; D000818:Animals; D001942:Breast Feeding; D002648:Child; D002675:Child, Preschool; D003072:Cognition Disorders / Q000139:chemically induced / Q000453:epidemiology*; D018736:DNA Adducts / Q000032:analysis / Q000633:toxicity*; D005260:Female; D006801:Humans; D007223:Infant; D008137:Longitudinal Studies; D008297:Male; D018811:Maternal Exposure; D011044:Poland / Q000453:epidemiology; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis / Q000633:toxicity*; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000453:epidemiology*; D012044:Regression Analysis; D012737:Sex Factors; D014028:Tobacco Smoke Pollution; D014888:Wechsler Scales
chemical_list: D000393:Air Pollutants; D018736:DNA Adducts; D011084:Polycyclic Aromatic Hydrocarbons; D014028:Tobacco Smoke Pollution; C095911:polycyclic aromatic hydrocarbons-DNA adduct