Mercury Not A Risk For Heart

Exposure to mercury does not increase the risk of coronary heart disease, stroke, or total cardiovascular disease, according to a study published by researchers at the Harvard School of Public Health.

Although health advisories warn women who are or may become pregnant to avoid consuming fish with a high quantities of mercury content, the study’s findings indicate that there is unlikely to be significant cardiovascular harm for the general public, said lead author Dariush Mozaffarian, an associate professor in epidemiology at the School of Public Health.

“For men—and women who aren’t planning to become pregnant—if they want to consume fish, they can take the concern for mercury level off the table when choosing a fish,” Mozaffarian said.

The study provides the most robust examination of the correlation between mercury levels and the risk of cardiovascular disease to date, Mozaffarian added.

The researchers analyzed data from two cohort groups from previous studies: 51,529 men from the Health Professionals Follow-Up Study and 121,700 women in the Nurses’ Health Study.

Scientists measured the mercury concentration in the subjects’ stored toenail clippings.

Then, the study identified 3,427 participants with cases of cardiovascular disease, which were matched with 3,427 controls who had not developed cardiovascular disease since their initial evaluation. The results showed that participants with higher mercury exposure did not have a higher risk of cardiovascular disease.

Professor of Epidemiology and Nutrition at the School of Public Health Eric B. Rimm, the study’s senior author, warned that “sensitive” populations, such as women who are pregnant or trying to be pregnant, and young children should remain cautious about an overconsumption of mercury.

Mozaffarian said the researchers next plan to look at whether mercury levels have other potential adverse effects, such as hypertension or risk of diabetes. However, the findings of the study are positive for those who want to incorporate more fish into their diet, as suggested by the 2010 Dietary Guidelines for Americans, Mozzaffarian said.

“Since cardiovascular disease is the leading cause of death in men and women and fish is the leading reducer of stroke, this is good news,” Mozaffarian said.

The study appeared in the Thursday edition of the New England Journal of Medicine.

—Staff writer Melanie A. Guzman can be reached at melanieguzman@college.harvard.edu.