Use of Magnetic Resonance Imaging Within a Molecular Epidemiologic Study of Air Pollution

Abstract

Introduction: Polycyclic aromatic hydrocarbons (PAH) are ubiquitous and neurotoxic combustion-related air contaminants. Prenatal PAH exposure has been associated with subsequent cognitive, emotional and behavioral problems in a birth cohort of New York City African-American and Latina children. Methods: To identify the effects of prenatal PAH exposure on brain structure and function, we have incorporated Magnetic Resonance Imaging of children within our ongoing study of the associations between prenatal PAH exposure of cognitive and behavioral outcomes in children. PAH exposure was measured by personal air monitoring during pregnancy and PAH-DNA adducts in cord and maternal blood at delivery. We conducted an initial study in a representative sample of 40 cohort study participants 7-9 yrs. to identify the effects of prenatal PAH exposure (measured by air monitoring) on brain structure and to assess the cognitive and behavioral correlates of those abnormalities. Imaging has been conducted in the larger cohort at age 9-12 and data are being analyzed. Results: In the initial study, we detected a significant dose-response relationship between increased prenatal PAH exposure and reductions of the white matter surface in the left hemisphere of the brain that were associated with slower information processing speed during intelligence testing and with more severe externalizing behavioral problems. Children are being reimaged at ages 14-18 to assess whether prenatal exposures to environmental PAH disrupt development and maturation of neural systems that support capacities for self-regulation of thought, emotion, and behavior. Conclusions: Our initial findings suggest prenatal exposure to PAH air pollutants may contribute to neurodevelopmental problems through alterations in brain development and are now being followed up in the cohort.