Background Polycyclic aromatic hydrocarbons are a common group of pollutants in the environment. Exposure to polycyclic aromatic hydrocarbons during pregnancy is a risk factor for adverse neurobehavioral development outcomes.
Objective This study is designed to evaluate the association between maternal exposure to polycyclic aromatic hydrocarbons during pregnancy and children's neurobehavioral development.
Methods A total of 158 mother-newborn pairs were collected from two hospitals in Taiyuan City, and the children were interviewed at age two. Urine samples were collected from the pregnant women waiting for delivery in hospital and the two-year-old children, and after the specific gravity of urine was measured, 11 urinary monohydroxylated polycyclic aromatic hydrocarbon metabolites (OH-PAHs) were detected by high performance liquid chromatography with tandem mass spectrometry. Children's neurobehavioral development was measured by Gesell Developmental Schedules. The Gesell Developmental Schedules consisted of four sub-scales:motor development, language development, adaptive behavior development, and personal-social behavior development, and each sub-scale generated a developmental quotient (DQ). DQ was standardized to 100±15; a DQ < 85 indicated growth retardation; a DQ of 70-84 indicated moderate neurobehavioral development disorder; a DQ < 70 indicated severe neurobehavioral development disorder. We used mean and standard deviation to describe continuous variables with normal distribution, median (interquartile range) or geometric mean (G) to describe continuous variables with skewed distribution, and frequency and proportion to describe categorical variables. Restricted cubic spline models were applied to assess the dose-response relationships between maternal prenatal polycyclic aromatic hydrocarbons exposure and children's neurobehavioral development at two years old. Generalized linear models were applied to evaluate the effect of exposure to maternal prenatal polycyclic aromatic hydrocarbons exposure on children's neurobehavioral development at two years old.
Results The motor, language, adaptive, and personal-social DQs were 116.00±14.53, 113.22±16.37, 114.70±13.94, and 115.67±14.26, respectively. There were 2, 5, 2, and 2 children generating a DQ < 85 for the four sub-scales respectively, and there was 1 child with a DQ < 70 for the language sub-scale, 1 child with a DQ < 70 for the adaptive sub-scale, and 1 child with a DQ < 70 for the personal-social subscale. Because the positive rates of 3-hydroxychrysene, 6-hydroxychrysene, and 9-hydroxybenzoapyrene were all lower than 50%, the study included the other eight OH-PAHs for further analysis. The G level of 2-hydroxyphenanthrene was the highest (0.09 μg·L-1), followed by 2-hydroxynaphthalene (0.07 μg·L-1), and 1-hydroxypyrene (0.07 μg·L-1) in maternal urine. The G level of total OH-PAHs (ΣOH-PAHs) in maternal urine was 0.62 μg·L-1. After adjusting for selected confounding factors, there were dose-response associations between maternal urinary 2-hydroxynaphthalene and children's motor DQ as well as between ∑OH-PAHs and motor DQ; a unit increase in urinary ln (2-hydroxynaphthalene) (b=-1.41, 95%CI:-2.74--0.08) or ln (∑OH-PAHs) (b=-2.09, 95%CI:-3.96--0.21) was associated with a decrease in motor DQ.
Conclusion Maternal exposure to polycyclic aromatic hydrocarbons during pregnancy is associated with decreased children's neurobehavioral development at two years old.
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