TY - JOUR

T1 - Association between mercury concentrations in blood and hair in methylmercury-exposed subjects at different ages

AU - Budtz-Jørgensen, Esben

AU - Grandjean, Philippe

AU - Jørgensen, Poul J.

AU - Weihe, Pál

AU - Keiding, Niels

N1 - Corrigendum to “Association between mercury concentrations in blood and hair in methylmercury-exposed subjects at different ages”: [Environ. Res. 95 (2004) 385–393]. A calculation error occurred in the conversion of units for the mercury measurements at age 7 years, i.e., both hair and blood results. The ratios between hair and blood are unchanged. Very little in the text needs to be changed, but one figure has the wrong scales (both axes). ...

PY - 2004/7

Y1 - 2004/7

N2 - Mercury concentrations were measured in paired hair and blood samples from a cohort of about 1000 children examined at birth and at 7 and 14 years of age. The ratio between concentrations in maternal hair (in microg/g) and in cord blood (microg/L) was approximately 200, but samples from the children at age 14 years showed a ratio of about 250. These findings are in accordance with previous data from smaller studies. However, an even higher ratio of about 360 was seen at 7 years of age, suggesting that hair strands at this age retain more mercury. The 95th percentile of the hair-to-blood ratio was between five-fold and nine-fold greater than the 5th percentile. The results were examined in structural equation models to estimate the total imprecision of the individual biomarker results and the possibility that the ratio may not be constant. The hair-to-blood ratio was found to increase at lower mercury concentrations, a tendency that could not be explained by potential confounders, such as alcohol intake or number of amalgam fillings. The total imprecision (coefficient of variation) for the blood determinations averaged about 30%, thereby substantially exceeding normal laboratory imprecision. Yet hair-mercury results had an even greater imprecision, which suggested that preanalytical factors, such as variable sample characteristics, impacted the results. These findings are in accordance with other evidence that the cord blood concentration is a better predictor of neurobehavioral toxicity than is the maternal hair concentration. Although practical for field studies and monitoring purposes, hair-mercury concentration results, therefore, need to be calibrated and interpreted in regard to each specific study setting.

AB - Mercury concentrations were measured in paired hair and blood samples from a cohort of about 1000 children examined at birth and at 7 and 14 years of age. The ratio between concentrations in maternal hair (in microg/g) and in cord blood (microg/L) was approximately 200, but samples from the children at age 14 years showed a ratio of about 250. These findings are in accordance with previous data from smaller studies. However, an even higher ratio of about 360 was seen at 7 years of age, suggesting that hair strands at this age retain more mercury. The 95th percentile of the hair-to-blood ratio was between five-fold and nine-fold greater than the 5th percentile. The results were examined in structural equation models to estimate the total imprecision of the individual biomarker results and the possibility that the ratio may not be constant. The hair-to-blood ratio was found to increase at lower mercury concentrations, a tendency that could not be explained by potential confounders, such as alcohol intake or number of amalgam fillings. The total imprecision (coefficient of variation) for the blood determinations averaged about 30%, thereby substantially exceeding normal laboratory imprecision. Yet hair-mercury results had an even greater imprecision, which suggested that preanalytical factors, such as variable sample characteristics, impacted the results. These findings are in accordance with other evidence that the cord blood concentration is a better predictor of neurobehavioral toxicity than is the maternal hair concentration. Although practical for field studies and monitoring purposes, hair-mercury concentration results, therefore, need to be calibrated and interpreted in regard to each specific study setting.

U2 - 10.1016/j.envres.2003.11.001

DO - 10.1016/j.envres.2003.11.001

M3 - Journal article

C2 - 15220072

VL - 95

SP - 385

EP - 393

JO - Environmental Research

JF - Environmental Research

SN - 0013-9351

IS - 3

ER -