Cognitive deficit in 7-year-old children with prenatal exposure to methylmercury.
A cohort of 1022 consecutive singleton births was generated during 1986-1987 in the Faroe Islands. Increased methylmercury exposure from maternal consumption of pilot whale meat was indicated by mercury concentrations in cord blood and maternal hair. At approximately 7 years of age, 917 of the children underwent detailed neurobehavioral examination. Neuropsychological tests included Finger Tapping; Hand-Eye Coordination; reaction time on a Continuous Performance Test; Wechsler Intelligence Scale for Children-Revised Digit Spans, Similarities, and Block Designs; Bender Visual Motor Gestalt Test; Boston Naming Test; and California Verbal Learning Test (Children). Clinical examination and neurophysiological testing did not reveal any clear-cut mercury-related abnormalities. However, mercury-related neuropsychological dysfunctions were most pronounced in the domains of language, attention, and memory, and to a lesser extent in visuospatial and motor functions. These associations remained after adjustment for covariates and after exclusion of children with maternal hair mercury concentrations above 10 microgram(s) (50 nmol/g). The effects on brain function associated with prenatal methylmercury exposure therefore appear widespread, and early dysfunction is detectable at exposure levels currently considered safe.
Grandjean
P
P
Institute of Community Health, Odense University, Denmark. p.grandjean@winsloew.ou.dk
Weihe
P
P
White
R F
RF
Debes
F
F
Araki
S
S
Yokoyama
K
K
Murata
K
K
Sørensen
N
N
Dahl
R
R
Jørgensen
P J
PJ
D000328:Adult; D001519:Behavior / Q000187:drug effects; D002648:Child; D003072:Cognition Disorders / Q000139:chemically induced* / Q000523:psychology; D004032:Diet; D016057:Evoked Potentials, Auditory, Brain Stem / Q000187:drug effects; D005074:Evoked Potentials, Visual / Q000502:physiology; D005260:Female; D006801:Humans; D007361:Intelligence Tests; D007858:Learning / Q000187:drug effects; D008767:Methylmercury Compounds / Q000506:poisoning*; D009483:Neuropsychological Tests; D011187:Posture / Q000502:physiology; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D011597:Psychomotor Performance / Q000187:drug effects
D008767:Methylmercury Compounds