title: Fish consumption, mercury exposure, and their associations with scholastic achievement in the Seychelles Child Development Study.
abstract: Studies of neurodevelopmental outcomes in offspring exposed to MeHg from maternal consumption of fish have primarily measured cognitive abilities. Reported associations have been subtle and in both adverse and beneficial directions. Changes in functional outcomes such as school achievement and behavior in exposed children and adolescents have not been examined. We undertook an assessment of school success of children in the Seychelles Child Development Study (SCDS) main cohort to determine if there were any associations with either prenatal or recent postnatal MeHg exposure. The primary endpoints were Seychelles nationally standardized end-of-year examinations given when the cohort children were 9 and 17 years of age. A subgroup (n=215) from the main cohort was also examined at 9 years of age using a regional achievement test called SACMEQ. Prenatal MeHg exposure was 6.8 ppm in maternal hair; recent postnatal exposure was 6.09 ppm at 9 years and 8.0 ppm at 17 years, measured in child hair. Multiple linear regression analyses showed no pattern of associations between prenatal or postnatal exposure, and either the 9- or 17-year end-of-year examination scores. For the subgroup of 215 subjects who participated in the SACMEQ test, there were significant adverse associations between examination scores and postnatal exposure, but only for males. The average postnatal exposure level in child hair for this subgroup was significantly higher than for the overall cohort. These results are consistent with our earlier studies and support the interpretation that prenatal MeHg exposure at dosages achieved by mothers consuming a diet high in fish are not associated with adverse educational measures of scholastic achievement. The adverse association of educational measures with postnatal exposure in males is intriguing, but will need to be confirmed by further studies examining factors that influence scholastic achievement.
authors.affiliation: University of Rochester, School of Medicine and Dentistry, Department of Pediatrics, Rochester, NY 14642, USA. davidsonph@aol.com
authors.forename: Philip W
authors.initials: PW
authors.lastname: Davidson
authors.forename: Andre
authors.initials: A
authors.lastname: Leste
authors.forename: Egbert
authors.initials: E
authors.lastname: Benstrong
authors.forename: Christine M
authors.initials: CM
authors.lastname: Burns
authors.forename: Justin
authors.initials: J
authors.lastname: Valentin
authors.forename: Jean
authors.initials: J
authors.lastname: Sloane-Reeves
authors.forename: Li-Shan
authors.initials: LS
authors.lastname: Huang
authors.forename: Wesley A
authors.initials: WA
authors.lastname: Miller
authors.forename: Douglas
authors.initials: D
authors.lastname: Gunzler
authors.forename: Edwin
authors.initials: E
authors.lastname: van Wijngaarden
authors.forename: Gene E
authors.initials: GE
authors.lastname: Watson
authors.forename: Grazyna
authors.initials: G
authors.lastname: Zareba
authors.forename: Conrad F
authors.initials: CF
authors.lastname: Shamlaye
authors.forename: Gary J
authors.initials: GJ
authors.lastname: Myers
mesh_terms: D000124:Achievement; D000293:Adolescent; D000367:Age Factors; D000818:Animals; D002648:Child; D015331:Cohort Studies; D002658:Developmental Disabilities / Q000139:chemically induced / Q000453:epidemiology / Q000503:physiopathology; D005260:Female; D005399:Fishes; D005506:Food Contamination / Q000706:statistics & numerical data*; D006197:Hair / Q000737:chemistry; D006801:Humans; D007804:Language Development; D008297:Male; D008767:Methylmercury Compounds / Q000009:adverse effects* / Q000378:metabolism; D009483:Neuropsychological Tests; D012044:Regression Analysis; D012189:Retrospective Studies; D012737:Sex Factors; D012750:Seychelles / Q000453:epidemiology; D013997:Time Factors
chemical_list: D008767:Methylmercury Compounds