Prenatal methylmercury exposure from ocean fish consumption in the Seychelles child development study.
BACKGROUND
Exposure to methylmercury (MeHg) before birth can adversely affect children's neurodevelopment. The most common form of prenatal exposure is maternal fish consumption, but whether such exposure harms the fetus is unknown. We aimed to identify adverse neurodevelopmental effects in a fish-consuming population.


METHODS
We investigated 779 mother-infant pairs residing in the Republic of Seychelles. Mothers reported consuming fish on average 12 meals per week. Fish in Seychelles contain much the same concentrations of MeHg as commercial ocean fish elsewhere. Prenatal MeHg exposure was determined from maternal hair growing during pregnancy. We assessed neurocognitive, language, memory, motor, perceptual-motor, and behavioural functions in children at age 9 years. The association between prenatal MeHg exposure and the primary endpoints was investigated with multiple linear regression with adjustment for covariates that affect child development.


RESULTS
Mean prenatal MeHg exposure was 6.9 parts per million (SD 4.5 ppm). Only two endpoints were associated with prenatal MeHg exposure. Increased exposure was associated with decreased performance in the grooved pegboard using the non-dominant hand in males and improved scores in the hyperactivity index of the Conner's teacher rating scale. Covariates affecting child development were appropriately associated with endpoints.


CONCLUSIONS
These data do not support the hypothesis that there is a neurodevelopmental risk from prenatal MeHg exposure resulting solely from ocean fish consumption.
Myers
Gary J
GJ
Department of Neurology, National Institute for Child Health and Development, National Institutes of Health, Department of Health and Human Services, Bethesda, USA. gary_myers@urmc.rochester.edu <gary_myers@urmc.rochester.edu>
Davidson
Philip W
PW
Cox
Christopher
C
Shamlaye
Conrad F
CF
Palumbo
Donna
D
Cernichiari
Elsa
E
Sloane-Reeves
Jean
J
Wilding
Gregory E
GE
Kost
James
J
Huang
Li-Shan
LS
Clarkson
Thomas W
TW
D000818:Animals; D002648:Child; D003072:Cognition Disorders / Q000139:chemically induced / Q000175:diagnosis / Q000453:epidemiology; D015331:Cohort Studies; D015897:Comorbidity; D004781:Environmental Exposure / Q000032:analysis*; D005260:Female; D005399:Fishes; D005500:Follow-Up Studies; D005506:Food Contamination / Q000032:analysis*; D006197:Hair / Q000737:chemistry; D006801:Humans; D007223:Infant; D008630:Mercury Poisoning / Q000453:epidemiology; D008767:Methylmercury Compounds / Q000009:adverse effects / Q000032:analysis*; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D012044:Regression Analysis; D017747:Seafood; D012750:Seychelles / Q000453:epidemiology
D008767:Methylmercury Compounds