Mercury, Fish Oils,
and the Risk of Myocardial Infarction
Eliseo Guallar, M.D., Dr.P.H., M. Inmaculada Sanz-Gallardo,
M.D., M.P.H., Pieter van't Veer, Ph.D., Peter Bode, Ph.D., Antti Aro, M.D.,
Ph.D., Jorge Gómez-Aracena, M.D., Ph.D., Jeremy D. Kark, M.D., Ph.D., Rudolph A.
Riemersma, Ph.D., José M. Martín-Moreno, M.D., Dr.P.H., Frans J. Kok, Ph.D., for
the Heavy Metals and Myocardial Infarction Study Group
Background It has been suggested that
mercury, a highly reactiveheavy metal with no known physiologic
activity, increases therisk of cardiovascular disease. Because fish
intake is a majorsource of exposure to mercury, the mercury content
of fish maycounteract the beneficial effects of its n3 fatty acids.
Methods In a casecontrol study conducted in eight European
countries and Israel, we evaluated the joint association ofmercury
levels in toenail clippings and docosahexaenoic acid(C22:6n3, or
DHA) levels in adipose tissue with the riskof a first myocardial
infarction among men. The patients were684 men with a first
diagnosis of myocardial infarction. Thecontrols were 724 men
selected to be representative of the samepopulations.
Results The average toenail mercury level in controls was 0.25µg per gram. After adjustment for the DHA level and coronary
risk factors, the mercury levels in the patients were 15 percent
higher than those in controls (95 percent confidence interval,5 to
25 percent). The risk-factoradjusted odds ratiofor myocardial
infarction associated with the highest as comparedwith the lowest
quintile of mercury was 2.16 (95 percent confidenceinterval, 1.09 to
4.29; P for trend=0.006). After adjustmentfor the mercury level, the
DHA level was inversely associatedwith the risk of myocardial
infarction (odds ratio for the highestvs. the lowest quintile, 0.59;
95 percent confidence interval,0.30 to 1.19; P for trend=0.02).
Conclusions The toenail mercury level was directly associatedwith the risk of myocardial infarction, and the adipose-tissue
DHA level was inversely associated with the risk. High mercury
content may diminish the cardioprotective effect of fish intake.
Source Information
From the Department of Epidemiology and Welch Center for
Prevention, Epidemiology and Clinical Research, Johns Hopkins Medical
Institutions, Baltimore (E.G.); the Department of Epidemiology and
Biostatistics, National School of Public Health, Institute of Health Carlos III,
Madrid (E.G., M.I.S.-G., J.M.M.-M.); the Service of Preventive Medicine,
Hospital 12 de Octubre, Madrid (M.I.S.-G.); the Division of Human Nutrition and
Epidemiology, University of Wageningen, Wageningen, the Netherlands (P.V., F.J.K.);
the Interfaculty Reactor Institute, Delft University of Technology, Delft, the
Netherlands (P.B.); the Department of Health and Functional Capacity, National
Public Health Institute, Helsinki, Finland (A.A.); the Department of Preventive
Medicine, University of Málaga, Málaga, Spain (J.G.-A.); the Epidemiology Unit,
Department of Social Medicine, Hadassah Medical Organization and Hebrew
UniversityHadassah School of Public Health and Community Medicine, Jerusalem,
Israel (J.D.K.); the Cardiovascular Research Unit, University of Edinburgh,
Edinburgh, United Kingdom, and the Department of Medical Physiology, University
of Tromsø, Tromsø, Norway (R.A.R.); and the Department of Preventive Medicine,
Universidad Autónoma de Madrid, Madrid (J.M.M.-M.)
Address reprint requests to Dr. Guallar at the Welch Center
for Prevention, Epidemiology, and Clinical Research, 2024 E. Monument St., Suite
2-639, Baltimore, MD 21205-2223, or at
eguallar@jhsph.edu.
Yoshizawa, K., Rimm, E. B., Morris, J. S., Spate, V. L., Hsieh, C.-c.,
Spiegelman, D., Stampfer, M. J., Willett, W. C. (2002). Mercury and the Risk
of Coronary Heart Disease in Men. N Engl J Med 347: 1755-1760 [Abstract][Full Text]
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