In Reply: We agree with Drs Mutter and Naumann
that forms of mercury other than methylmercury may have an impact on neurobehavioral
function. The major sources of mercury exposure in the general US adult population
are fish (methylmercury) and dental amalgams (elemental mercury).1 Both of these exposures are correlated with levels
of mercury in blood, urine, and hair,1 so total
blood mercury should have captured both sources. The study on mercury vapor
that they cite2 examined only 47 primarily
white (92%) dental workers with occupational exposure to elemental mercury,
so it is not clear whether this study is relevant to the general population.
The study may be flawed in 2 other respects: (1) it appears that the study
participants represented a convenience sample, and (2) part of the dose assessment
was based on urinary mercury concentration after administration of a chelating
agent, a method that has not been adequately validated.
Blood Mercury Levels and Neurobehavior—Reply. JAMA. 2005;294(6):679-680. doi:10.1001/jama.294.6.679-b