Blood Mercury Levels in U.S. Children and Women of Childbearing Age, 1999-2000

The Scientific Paper:

Susan E. Schober, Thomas E. Sinks, Robert L. Jones, P. Michael Bolger, Margaret McDowell, Josh Osterloh, E. Spencer Garrett, Richard A. Canady, Charles F. Dillion, Yu Sun, Catherine B. Joseph, and Kathryn R. Mahaffey. Journal of the American Medical Association (JAMA). Vol. 289. No. 13. pp 1667-1674. 2003.

Review This Scientific Paper’s Abstract:
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db
=PubMed&list_uids=12672735&dopt=Citation

The Purpose of this Study:
These scientists attempt to describe the distribution of blood mercury levels in U.S. children and in women of childbearing age to see if this distribution varies with the societal and/or the regional differences of eating fish.

Some Background, Methods, Results, Caveats, and Other Select Points:

• This peer-reviewed, scientific paper was published in 2003.
• These scientists reviewed the 1999-2000 National Health and Nutrition Examination Survey (NHANES) data collected by the Centers for Disease Control and Prevention (CDC). As part of the NHANES study, the CDC conducted household interviews, performed physical examinations, and analyzed the blood mercury levels of 705 children and 1,709 women. These scientists reported on these data and related study findings to provide estimates of the blood mercury levels in U.S. women and children. These scientists also describe how blood mercury levels vary by the types and amounts of fish and shellfish eaten by U.S. women and children.
• These reported methylmercury levels were measured only among children aged 1 to 5 years and in women of childbearing age.
• The 1999-2000 NHANES study was not designed to describe geographic variation because of the relatively small number of geographic sites sampled.
• Income-based information on socioeconomic status was not available from the 1999-2000 NHANES study.
• The EPA methylmercury reference dose is an estimate of the highest daily dose of methylmercury that the most sensitive person in the population can be exposed to over a lifetime without experiencing any bad effects. The EPA methylmercury reference dose applies a 10-fold safety factor to the EPA benchmark dose lower level (BMDL) for methylmercury. The methylmercury BMDL is the lowest amount at which a bad effect can still occur in people.
• In the 1999-2000 NHANES study, no women had blood mercury concentrations at the EPA methylmercury benchmark dose lower level (BMDL). The EPA methylmercury BMDL is the lowest amount of methylmercury that can cause a bad effect in people.
• About 8 percent of these women had blood methylmercury concentrations higher than the EPA methylmercury reference dose. Levels below the EPA methylmercury reference dose are believed by the EPA and others to be essentially safe for people.

A Bottom Line:

• Based on the NHANES data, these scientists report that total mercury exposure in women of childbearing age — and also in young children — generally fall below levels of concern for their safety.
• Blood mercury levels increased with increased eating of fish and shellfish.
• Eating shellfish, independent of eating fish, is related with blood mercury levels in women - but not in children.
• Blood mercury levels were 3 times higher in women than in young children. The difference may be due to a number of things - including portion size of a seafood meal and how often seafood meals are eaten.
• These scientists recommend that women who are pregnant or who may become pregnant should follow all federal and state advisories about eating fish.

Find This Scientific Paper for Your Review:
Blood Mercury Levels in U.S. Children and Women of Childbearing Age, 1999-2000. Journal of the American Medical Association (JAMA) Vol. 289. No.13. pp 1667-1674. 2003.