Myocardial infarction in relation to mercury and fatty acids from fish: a risk-benefit analysis based on pooled Finnish and Swedish data in men.
BACKGROUND
Exposure to methylmercury from fish has been associated with increased risk of myocardial infarction (MI) in some studies. At the same time, marine n-3 (omega-3) PUFAs are an inherent constituent of fish and are regarded as beneficial. To our knowledge, no risk-benefit model on the basis of data on methylmercury, PUFA, and MI risk has yet been presented.


OBJECTIVE
The objective of this study was to describe how exposure to both marine n-3 PUFAs and methylmercury relates to MI risk by using data from Finland and Sweden.


METHODS
We used matched case-control sets from Sweden and Finland that were nested in population-based, prospective cohort studies. We included 361 men with MI from Sweden and 211 men with MI from Finland. MI risk was estimated in a logistic regression model with the amount of mercury in hair (hair-Hg) and concentrations of n-3 PUFAs (EPA and DHA) in serum (S-PUFA) as independent variables.


RESULTS
The median hair-Hg was 0.57 μg/g in Swedish and 1.32 μg/g in Finnish control subjects, whereas the percentage of S-PUFA was 4.21% and 3.83%, respectively. In combined analysis, hair-Hg was associated with higher (P = 0.005) and S-PUFA with lower (P = 0.011) MI risk. Our model indicated that even a small change in fish consumption (ie, by increasing S-PUFA by 1%) would prevent 7% of MIs, despite a small increase in mercury exposure. However, at a high hair-Hg, the modeled beneficial effect of PUFA on MI risk was counteracted by methylmercury.


CONCLUSIONS
Exposure to methylmercury was associated with increased risk of MI, and higher S-PUFA concentrations were associated with decreased risk of MI. Thus, MI risk may be reduced by the consumption of fish high in PUFAs and low in methylmercury.
Departments of Public Health and Clinical Medicine, Occupational and Environmental Medicine, Umeå University, Umeå, Sweden. maria.wennberg@envmed.umu.se
Maria
M
Wennberg
Ulf
U
Strömberg
Ingvar A
IA
Bergdahl
Jan-Håkan
JH
Jansson
Jussi
J
Kauhanen
Margareta
M
Norberg
Jukka T
JT
Salonen
Staffan
S
Skerfving
Tomi-Pekka
TP
Tuomainen
Bengt
B
Vessby
Jyrki K
JK
Virtanen
D000328:Adult; D000368:Aged; D000818:Animals; D016022:Case-Control Studies; D015331:Cohort Studies; D015525:Fatty Acids, Omega-3 / Q000008:administration & dosage / Q000097:blood*; D005387:Finland; D005399:Fishes; D005506:Food Contamination; D006197:Hair / Q000737:chemistry; D006801:Humans; D016015:Logistic Models; D008297:Male; D008628:Mercury / Q000032:analysis; D008630:Mercury Poisoning / Q000209:etiology / Q000503:physiopathology*; D008767:Methylmercury Compounds / Q000008:administration & dosage / Q000633:toxicity; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood / Q000209:etiology* / Q000378:metabolism / Q000517:prevention & control*; D011446:Prospective Studies; D018570:Risk Assessment; D017747:Seafood / Q000009:adverse effects*; D013548:Sweden
D015525:Fatty Acids, Omega-3; D008767:Methylmercury Compounds; D008628:Mercury