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24-03-2011 | Cardiology | Article

Mercury exposure unlikely to raise CVD risk


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MedWire News: Results from a US study indicate that exposure to mercury from eating fish does not increase the risk for coronary heart disease (CHD), stroke, or total cardiovascular disease (CVD).

"These findings suggest that people need not worry about cardiovascular harm from mercury exposure when deciding whether to consume fish," said lead author Dariush Mozaffarian (Harvard Medical School, Boston, Massachusetts).

"Public health efforts to reduce mercury in the environment should continue, as mercury exposure can have other harmful effects, for example on neurodevelopment during infancy," he added.

Mozaffarian and colleagues analyzed data from two studies involving a total of 51,529 men aged 40-75 years and 121,700 women aged 30-55 years.

Mercury concentrations were measured by taking toenail clippings from all participants - an assessment method that the researchers say accurately reflects long-term mercury exposure.

Over a median follow-up period of 11.3 years, 3427 participants developed CVD (defined as CHD or stroke).

The researchers report that when these individuals were matched by age, gender, and smoking status with 3427 CVD-free controls, mercury exposure levels were unrelated to CVD development.

Indeed, the case and control participants had similar median mercury concentration levels, at 0.23 and 0.25 µg/g, respectively.

When participants' outcomes were compared across quintiles of increasing mercury exposure, no significant relationship was seen between level of mercury exposure and risk for CVD. For example, participants in the top quintile of exposure had nonsignificant relative risks for CHD, stroke, and total CVD of 0.85, 0.84, and 0.85 compared with those in the bottom quintile.

Writing in NEJM, the authors say that their findings support 2010 US dietary guidelines that advocate the cardioprotective benefits of increasing seafood consumption.

However, they emphasize: "Our findings should also not alter advisories directed toward women who are or may become pregnant or who are nursing, since methylmercury exposure from consumption of specific fish species could cause neurodevelopmental harm, or at least offset the neurodevelopmental benefits of fish consumption, in their children."

MedWire ( is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2011

By Lauretta Ihonor

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