| Umbilical Cord Mercury Concentration
as Biomarker of Prenatal Exposure
to Methylmercury Philippe Grandjean,1,2 Esben Budtz-Jørgensen,1,3 Poul
J. Jørgensen,4 and Pál Weihe1,5 1Institute of Public Health, University of Southern Denmark, Odense,
Denmark; 2Department of Environmental Health, Harvard School of
Public Health, Boston, Massachusetts, USA; 3Department of Biostatistics,
Institute of Public Health, University of Copenhagen, Copenhagen, Denmark; 4Institute
of Clinical Research, Odense University Hospital, Odense, Denmark; 5Faroese
Hospital System, Tórshavn, Faroe Islands Abstract
Biomarkers are often applied to assess prenatal exposure to methylmercury in research and surveillance. In a prospective study in the Faroe Islands, the main exposure biomarkers were the mercury concentrations in cord blood and maternal hair obtained at parturition. We have now supplemented these exposure biomarkers with mercury analyses of umbilical cord tissue from 447 births. In particular, when expressed in relation to the dry weight of the tissue, the cord mercury concentration correlated very well with that in cord blood. Structural equation model analysis showed that these two biomarkers have average total imprecision of about 30%, which is much higher than the laboratory error. The imprecision of the dry-weight-based concentration was lower than that of the wet-weight-based parameter, and it was intermediate between those of the cord blood and the hair biomarkers. In agreement with this finding, regression analyses showed that the dry-weight cord mercury concentration was almost as good a predictor of methylmercury-associated neuropsychologic deficits at 7 years of age as was the cord-blood mercury concentration. Cord mercury analysis can therefore be used as a valid measure of prenatal methylmercury exposure, but appropriate adjustment for the imprecision should be considered. Key words: biomarker, exposure assessment, food contamination, hair analysis, mercury/analysis, methylmercury compounds/analysis, organomercury compounds/blood, pregnancy, prenatal exposure delayed effects, preschool child, seafood, umbilical cord. Environ Health Perspect 113:905-908 (2005) . doi:10.1289/ehp.7842 available via http://dx.doi.org/ [Online 31 March 2005]
Address correspondence to P. Grandjean, Institute of Public Health, University of Southern Denmark, Winslowparken 17, 5000 Odense, Denmark. Telephone: 45-6550-3769. Fax: 45-6591-1458. E-mail: pgrand@health.sdu.dk We gratefully acknowledge the technical support by B. Andersen. This study was supported by the U.S. National Institute of Environmental Health Sciences (ES09797) and the Danish Medical Research Council. The contents of this article are solely the responsibility of the authors and do not represent the official views of the National Institute of Environmental Health Sciences, National Institutes of Health, or any other funding agency. The authors declare they have no competing financial interests. Received 10 December 2004 ; accepted 31 March 2005. The full version of this article is available for free in HTML or PDF formats. |
