Prenatal and Concurrent Mercury Exposure and Measures of Attention in Children from Mexico City

Abstract

Prenatal and Concurrent Mercury Exposure and Measures of Attention in Children from Mexico CityAbstract Number:2716 Rebecca Tutino*, Niladri Basu, Lourdes Schnaas, Brisa Sanchez, Karen E. Peterson, Mauricio Hernandez-Avila, Howard Hu, and Martha Maria Tellez-Rojo Rebecca Tutino* University of Michigan School of Public Health, United States, E-mail Address: [email protected] Search for more papers by this author , Niladri Basu McGill University, Canada, E-mail Address: [email protected] Search for more papers by this author , Lourdes Schnaas Instituto Nacional de Perinatología, Mexico, E-mail Address: [email protected] Search for more papers by this author , Brisa Sanchez University of Michigan School of Public Health, United States, E-mail Address: [email protected] Search for more papers by this author , Karen E. Peterson University of Michigan School of Public Health, United States, E-mail Address: [email protected] Search for more papers by this author , Mauricio Hernandez-Avila Centro de Investigaciones en Salud Pública Instituto Nacional de Salud Pública, Mexico, E-mail Address: [email protected] Search for more papers by this author , Howard Hu University of Toronto Dalla Lana School of Public Health, United States, E-mail Address: [email protected] Search for more papers by this author , and Martha Maria Tellez-Rojo Centro de Investigaciones en Salud Pública Instituto Nacional de Salud Pública, Mexico, E-mail Address: [email protected] Search for more papers by this author AbstractAttention deficit-hyperactivity disorder (ADHD) is the most common neurological disorder among school-aged children. Prenatal exposure to the neurotoxicant methylmercury (MeHg) has been related to ADHD symptoms, but impact of exposures in different trimesters is not well understood. Further, there is little evidence that postnatal exposures are relevant, and little is known about inorganic mercury exposures. We examined the relationship between MeHg exposure in venous blood from each trimester of pregnancy and umbilical cord blood (n=202), as well as concurrent exposures (n=770) to MeHg and inorganic Hg, with the clinical profile confidence index of the Conners’ Continuous Performance Test II (CPTII) at 6-18 years of age in Early Life Exposure in Mexico to Environmental Toxicants (ELEMENT) birth cohorts. Venous blood was collected from pregnant mothers during each trimester and averaged 3.9μg/L Hg; cord blood (4.5μg/L Hg) was collected at birth. Blood, hair, and urine were collected from children at each follow-up visit and averaged 1.9μg/L, 0.5μg/g, and 1.0μg/L, respectively. Mean CPTII clinical confidence score was 46.9. Multivariable linear regression models for each time point estimated the association of log-transformed MeHg exposures with CPTII clinical profile, adjusted for child age and sex, maternal characteristics, and socioeconomic status. We found no associations with MeHg exposure during pregnancy. After stratification by study cohort, an association between log-transformed third trimester MeHg and clinical score (ß=6.12, p=0.035) was observed in the cohort with older children. No associations were observed with concurrent MeHg exposure. These observations may help refine our current understanding of prenatal MeHg exposure’s impact on later behavioral outcomes. Additional work is underway to examine the characteristics of the cohorts that might contribute to the differential responses.