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Autism Spectrum Disorder Phenotypes and Prenatal Exposure to Methylmercury

van Wijngaarden, Edwina,b,c; Davidson, Philip W.d,e; Smith, Tristram H.d; Evans, Katief; Yost, Kelleyd; Love, Tanzyf; Thurston, Sally W.f; Watson, Gene E.b,c; Zareba, Grazynab; Burns, Christine M.d; Shamlaye, Conrad F.g; Myers, Gary J.h,b,d

doi: 10.1097/EDE.0b013e31829d2651
Neurobehavior

Background: There continues to be public concern that mercury exposure and autism spectrum disorder (ASD) may be associated. The primary source of exposure to organic mercury in humans is to methylmercury from fish consumption. We evaluated the association between prenatal methylmercury exposure and ASD phenotype in children and adolescents in the Republic of Seychelles, where fish consumption is high.

Methods: We administered the Social Communication Questionnaire to parents of a cohort of 1784 children, adolescents, and young adults. The Social Responsiveness Scale was administered to teachers of 537 cohort subjects at about 10 years of age. Prenatal exposure to methylmercury was measured in maternal hair samples collected at or near the time of birth. Multivariable regression models evaluated the relationship between prenatal methylmercury exposure and ASD phenotypic scores, adjusting for relevant covariates.

Results: The mean prenatal methylmercury exposure for subjects in the analysis was 8.4 ppm (standard deviation [SD] = 5.7). The mean Social Communication Questionnaire score was 8.0 (SD = 4.4). The mean prenatal methylmercury exposure for subjects with Social Responsiveness Scale scores was 6.7 ppm (SD = 4.4) and the mean Social Responsiveness Scale score was 57.6 (SD = 26.8). No consistent association between prenatal methylmercury exposure and ASD screening instrument was found, using linear and nonlinear regression analyses.

Conclusions: Prenatal exposure to methylmercury was not associated with ASD phenotypic behaviors in our cohort of high fish consumers. Our findings contribute to the growing literature suggesting that exposure to methylmercury does not play an important role in the development of ASD phenotypic behavior.

From the aDepartment of Public Health Sciences, University of Rochester School of Medicine and Dentistry, Rochester, NY; bDepartment of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY; cEastman Department of Dentistry, University of Rochester School of Medicine and Dentistry, Rochester, NY; dDepartment of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, NY; eDepartment of Psychiatry, University of Rochester School of Medicine and Dentistry, Rochester, NY; fDepartment of Biostatistics, University of Rochester School of Medicine and Dentistry, Rochester, NY; gSeychelles Ministry of Health, Victoria, Mahé, Seychelles; and hDepartment of Neurology, University of Rochester School of Medicine and Dentistry, Rochester, NY.

This research was supported by grants R21-ES-15487, RO1-ES010219, R01-ES-015578, R01-ES-08442, P30-ES01247, and T32-ES007271 from the US National Institute of Environmental Health Sciences, National Institutes of Health, and by the Government of the Republic of Seychelles.

The authors report no conflicts of interest.

Correspondence: Edwin van Wijngaarden, Department of Public Health Sciences, University of Rochester School of Medicine and Dentistry, 265 Crittenden Blvd., CU 420644, Rochester, NY 14642. E-mail: edwin_van_wijngaarden@urmc.rochester.edu.

Received November 21, 2012

Accepted March 11, 2013

© 2013 by Lippincott Williams & Wilkins, Inc