Blood mercury levels in US children and women of childbearing age, 1999-2000.
BACKGROUND
Humans are exposed to methylmercury, a well-established neurotoxin, through fish consumption. The fetus is most sensitive to the adverse effects of exposure. The extent of exposure to methylmercury in US women of reproductive age is not known.


OBJECTIVE
To describe the distribution of blood mercury levels in US children and women of childbearing age and the association with sociodemographic characteristics and fish consumption.


METHODS
The 1999-2000 data from the National Health and Nutrition Examination Survey, a cross-sectional survey of the noninstitutionalized US population.


METHODS
In 1999-2000, 1250 children aged 1 to 5 years and 2314 women aged 16 to 49 years were selected to participate in the survey. Household interviews, physical examinations, and blood mercury levels assessments were performed on 705 children (56% response rate) and 1709 women (74% response rate).


METHODS
Blood concentration of total mercury.


RESULTS
Blood mercury levels were approximately 3-fold higher in women compared with children. The geometric mean concentration of total blood mercury was 0.34 micro g/L (95% confidence interval [CI], 0.30-0.39 microg/L) in children and 1.02 microg/L (95% CI, 0.85-1.20 microg/L) in women. Geometric mean mercury levels were almost 4-fold higher among women who ate 3 or more servings of fish in the past 30 days compared with women who ate no fish in that period (1.94 microg/L vs 0.51 microg/L; P<.001).


CONCLUSIONS
Measures of mercury exposure in women of childbearing age and young children generally fall below levels of concern. However, approximately 8% of women had concentrations higher than the US Environmental Protection Agency's recommended reference dose (5.8 microg/L), below which exposures are considered to be without adverse effects. Women who are pregnant or who intend to become pregnant should follow federal and state advisories on consumption of fish.
Schober
Susan E
SE
National Center for Health Statistics, Centers for Disease Control and Prevention, Hyattsville, Md 20782, USA. sschober@cdc.gov
Sinks
Thomas H
TH
Jones
Robert L
RL
Bolger
P Michael
PM
McDowell
Margaret
M
Osterloh
John
J
Garrett
E Spencer
ES
Canady
Richard A
RA
Dillon
Charles F
CF
Sun
Yu
Y
Joseph
Catherine B
CB
Mahaffey
Kathryn R
KR
D000293:Adolescent; D000328:Adult; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D003710:Demography; D004781:Environmental Exposure / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008628:Mercury / Q000097:blood*; D008767:Methylmercury Compounds / Q000378:metabolism; D008875:Middle Aged; D009749:Nutrition Surveys; D017747:Seafood; D014481:United States / Q000453:epidemiology
D008767:Methylmercury Compounds; D008628:Mercury