Too much fish?

[Guest guest]

If you eat fish daily, perhaps a pacemaker is in order

Mike

http://tinyurl.com/f9yuf

No paper yet....

BOSTON, May 18 — Five or more servings of fish per week led to a

significantly increased risk for atrial fibrillation, according to a

review of more than 17,000 men.

" In this large prospective cohort of apparently healthy men, in both

unadjusted and maximally adjusted models, fish consumption was

associated with increased risk of adult atrial fibrillation, " said

electrophysiologist Aizer, M.D., M.Sc., of New York

University, and colleagues.

Similarly, in both adjusted and unadjusted models, increased omega-3

fatty acid consumption was also associated with increased risk of

atrial fibrillation, he reported at the Heart Rhythm Society meeting

here.

Still, the protective benefits of fish consumption still far

outweigh the theoretical increased risk of atrial fibrillation, Dr.

Aizer emphasized.

" The message of this study is not to stop eating fish, " he

said. " Atrial fibrillation is a complex condition that requires the

interaction of a number of factors to develop. Fish may have

different effects on different people. Lifestyle and dietary habits

need to be tailored on an individual basis to promote overall

health. "

The results corroborate those of the Danish Diet Cancer and Health

study of nearly 48,000 middle-age people, which found that

calculated omega-3 fatty acid consumption was associated with an

increased risk for developing atrial fibrillation.

On the other hand, the current study contradicts the Cardiovascular

Healthy Study of 4,815 people ages 65 years and older, which found

that people who ate fish had a reduced risk for developing atrial

fibrillation.

The researchers looked at men who were enrolled in the Physicians'

Health Study, 17,679 of whom reported that they did not take omega-e

fatty acid dietary supplements at baseline. The men provided

detailed information about their fish consumption at one year follow-

up, with a four-item questionnaire that asked about the frequency of

fish consumption and they type consumed (for example, canned tuna,

dark meat fish such as mackerel or bluefish, crustaceans, or other

fish).

At a 15-year follow-up the physician participants were asked to

report whether they had been diagnosed with atrial fibrillation, and

the date of diagnosis, or with any other new disease.

A total of 1,253 (7.1%) of the participants developed atrial

fibrillation during follow-up.

In an analysis adjusted for age and randomized treatment assignment

(i.e., aspirin or placebo or beta-carotene or placebo), the authors

found that fish consumption was associated with an increased risk

for developing atrial fibrillation.

Men who ate fish once a month or less had no increased risk, whereas

men who ate fish two to four times a week had a relative risk of

1.41 (95% confidence interval, 0.84-1.89), and men who had five or

more servings of aquatic fare each week had a relative risk of 1.55

(95% CI, 1.02-2.37, P value for the trend = 0.008).

Additionally, when the investigators controlled for age, treatment

assignment, cardiovascular-disease risk factors and lifestyle, they

found that men in the highest two fish-consumption categories still

had relative risks of 1.32 (95% CI, 0.87-2.01) and 1.46 (95% CI,

0.94-2.28), respectively.

In addition calculated (estimated) omega-3 fatty acid consumption

was also associated with an increased risk of developing atrial

fibrillation. The adjusted odds ratio was 1.37; (95% CI, 0.90-2.10)

for the highest versus the lowest fifth of fish eating, P for trend

= 0.017).

Dr. Aizer said that the divergent results of the various health

studies with regard to a fish-atrial fibrillation connection may

have to do with heterogeneity across the various cohorts. For

example, in the Physicians' Health Study and the Danish study the

populations were younger, had less hypertension, and were excluded

from the study if they had cardiovascular disease at baseline, in

contrast to patients in the Cardiovascular Healthy Study.

" So it is possible that potential pro-fibrillatory effects of omega-

3 fatty acids may have a more significant impact in young

individuals without cardiovascular disease, where vagal tone may

have a more significant role, while in contrast, the anti-

fibrillatory effects of omega-3 fatty acids may have a more

significant impact on older individuals with cardiovascular

disease, " Dr. Aizer said.

He noted that in the Physicians' Health Study population, fish

consumption was associated with lower risk of ventricular

fibrillation and sudden cardiac death.

Primary source: 2006 Heart Rhythm Society Meeting

Source reference:

Aizer A et al. " Relationship between fish consumption and the

development of atrial fibrillation in men. " Abstract AB03-2,

presented May 18, 2006.