Mercury exposure - even at low levels - linked to eczema.
Park, H, and K Kim. 2011. Association of blood mercury concentrations with atopic dermatitis in adults: A population-based study in Korea. Environmental Research http://dx.doi.org/10.1016/j.envres.2011.02.003.
Mercury exposure – possibly through eating seafood – is linked to a greater risk of contracting atopic dermatitis, a common skin disease known more commonly as eczema, report Korean researchers in the journal Environmental Research.
Results from this study are among the first to show a link between mercury and the common skin condition, which is rising in industrialized countries. Effects were seen at and below mercury blood levels deemed safe by U.S. agencies.
The study's findings provide further evidence of an effect of mercury on the immune system.
Causes of eczema elude experts but most agree genetic, immune and environmental factors combine to increase disease risk. Symptoms include dry, itchy patches that can lead to unsightly red and inflamed skin. The persistent condition can affect personal and professional lives.
Mercury is a toxic chemical found globally throughout the environment. Most people are exposed to a particularly toxic form of mercury – known as methylmercury – from eating seafood. Scientists agree that mercury can harm the developing fetus and children.
However, the risk of exposure to mercury and health effects from eating fish in adults is under debate. Recent research has suggested that mercury can harm the immune system. Another line of research has found a rapid increase in eczema that may be linked to environmental factors.
Researchers recruited approximately 2,000 adults in Korea. They measured mercury concentrations in blood, diet habits and medical history of eczema. They then compared the number of adults reporting a history of eczema in people with low versus high blood mercury levels.
The scientists found that adults with high blood mercury levels were 50 percent more likely to report having eczema throughout their lifetime and were almost twice as likely to have eczema within the last year. Finally, the scientists found that increased risk for eczema can occur at blood mercury levels that are at or below five micrograms per liter, the level currently considered safe in the United States.
Blood mercury levels were associated with fish and shellfish consumption, implicating fish as the likely route of exposure to mercury. However, the researchers cannot rule out whether some participants were exposed to mercury through other means, such as through their occupation.
After age, gender and other possible cofactors were taken into account by the researchers, the results suggest that even low levels of mercury exposure can have clinical effects in adults, possibly by acting through the immune system. While the results do not establish that mercury exposure directly causes eczema, the results raise the question of how mercury may play a role in the common skin disease and on the immune system in general.
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