The Seychelles study of fetal methylmercury exposure and child development: introduction.
Studies of outbreaks of methylmercury poisoning in Japan and Iraq from consumption of methylmercury (MeHg)-contaminated fish or bread proved that brain was the target organ, the toxic effects were dose-related, and the fetal brain was especially susceptible. Previous population studies suggested that a 5% risk of minimal fetal effect may be associated with a maternal hair mercury concentration during pregnancy of 10-20 ppm (mu g/g), a level that can be readily achieved by frequent consumers of fish. However, these studies had limitations, and as a result no definite conclusion concerning the lowest effect level could be reached and the question of a possible hazard to public health remained unanswered. There was a clear need for a more definitive study that would be prospective, involve a large enough cohort for risk analysis and adhere to accepted epidemiological principles. An appropriate site for such a study is the Republic of Seychelles, a location that afforded successful collaboration between the Seychelles Ministry of Health and faculty of the University of Rochester. A pilot study of 804 infant-mother pairs was followed by a main study of 779 mother-infant pairs. In the pilot study children were examined once between 5 and 109 weeks of age; in the main study they are being evaluated longitudinally starting at 6 1/2 months of age. This paper introduces both the pilot and main studies, describes their design, and summarizes the findings through 6 1/2 months of age. When the Seychelles study is completed, the analyses will provide a database for those nations that choose to regulate their citizens' fish consumption and/or provide dietary education.
Marsh
D O
DO
Department of Neurology, University of Rochester School of Medicine, New York 14642, USA.
Clarkson
T W
TW
Myers
G J
GJ
Davidson
P W
PW
Cox
C
C
Cernichiari
E
E
Tanner
M A
MA
Lednar
W
W
Shamlaye
C
C
Choisy
O
O
D002648:Child; D002657:Child Development / Q000187:drug effects*; D004781:Environmental Exposure; D004782:Environmental Health; D005260:Female; D006801:Humans; D008431:Maternal-Fetal Exchange; D008628:Mercury / Q000633:toxicity*; D011247:Pregnancy; D012750:Seychelles
D008628:Mercury