SUMMARY OF THE SEYCHELLES CHILD-DEVELOPMENT STUDY ON THE RELATIONSHIPOF FETAL METHYLMERCURY EXPOSURE TO NEURODEVELOPMENT

The Seychelles Child Development Study is examining the association be tween fetal methylmercury exposure from a maternal diet high in fish a nd subsequent child development. The study is double blind and uses ma ternal hair mercury as the index of fetal exposure. An initial cross-s ectional pilot study of 804 infants aged 1 to 25 months suggested that mercury may affect development A follow up of 217 pilot children at 6 6 months of age also suggested that neurodevelopmental effects might b e present, but the result was dependent on outcomes in a small number of children. On the basis of initial results in the pilot study a pros pective, longitudinal main study with more covariates and expanded end points was begun on a new cohort of 779 children. No association with neurodevelopment was seen at 6 1/2, 19, or 29 months of age, but there was an inverse relationship at 29 months in boys only between mercury level and activity as judged by the examiner. Adverse neurodevelopmen tal effects from fetal mercury exposure in the pilot study are highly dependent on how the data are analyzed and no definite effects have be en detected through 29 months of age in the main study. In a related s tudy, 32 brains were obtained at autopsy from Seychellois infants. The se were examined histologically and analyzed for mercury. No clear his tological abnormalities were found. Mercury levels ranged from a backg round of about 50 ppb up to 300 ppb, and correlated well between brain regions. For 27 brains maternal hair from delivery was available and hair mercury correlated well with brain mercury. (C) 1995 Intox Press, Inc.