Men who eat fish once a month or more have a reduced risk of ischemic stroke, compared with those who eat fish less often, according to researchers reporting in the December 25 issue of The Journal of the American Medical Association (JAMA).

The authors noted that the effect of fish consumption or long-chain omega-3 polyunsaturated fatty acid (PUFA) intake on risk of stroke remains uncertain. They set out to examine further this relation between fish intake and risk of stroke in men.

Dr Ka He, from the Harvard School of Public Health, Boston, and colleagues, studied more than 43,000 men participating in the Health Professional Follow-up Study (HPFS), a large cohort of men who periodically completed dietary measurements during 12 years of follow-up.

The men aged 40 to 75 years completed a detailed and validated food frequency questionnaire and were free from cardiovascular diseases at baseline in 1986. The researchers determined the relative risk (RR) of stroke by subtype based on the cumulative average fish consumption or long-chain Omega-3 fatty acid intake, ascertained in 1986, 1990, and 1994.

In the 12 year follow-up, 608 participants developed stroke. Among these cases, 377 were confirmed as ischemic stroke, 106 were identified as haemorrhagic stroke, and the remainder could not be classified from the available medical documentation.

"For cumulative average fish consumption, the risk of ischemic stroke was lower among men in each category of fish consumption compared with those who ate fish less than once per month. Even a small amount of fish consumption (1-3 times per month) was associated with a significant reduction of 43 percent in risk of ischemic stroke," wrote the authors.

However no further benefit was observed at higher levels of fish intake. The RR for those who ate fish five or more times per week was 46 percent lower, they said.

Men who consumed fish at least once per month had a 44 percent lower risk of ischemic stroke compared with those who ate fish less than once per month. Risk of haemorrhagic stroke was not significantly associated with fish intake.