Fatty Acid Consumption Lowers Risk Among Some Middle-Aged Women.(stroke )

2001 FEB 1 - (NewsRx.com) -- Higher consumption of fish and n3 polyunsaturated fatty acids is associated with a reduced risk of some types of stroke among middle-aged women, and primarily among women who do not take aspirin regularly.

Hiroyasu Iso, MD, PhD, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, and colleagues followed 79,839 women over a period of 14 years, from 1980-1994. The women ranged in age from 34 to 59 at the start of the prospective study period. All were enrolled in the Nurses' Health Study, which collected information on lifestyles and medical history from female nurses in 11 states.

The researchers' findings were published in the January 17, 2001, issue of The Journal of the American Medical Association. According to background information cited by the authors, an inverse relationship between fish intake and risk of stroke has been reported in several, but not all, prospective studies. But no prospective study has previously examined the relationship between intake of fish and n3 fatty acids and stroke risk, by stroke subtypes.

According to The American Medical Association Encyclopedia of Medicine, stroke may be caused by any of three mechanisms. Thrombosis is blockage by a thrombus, or clot, that has built up on the wall of a brain artery. It accounts for 40% to 50% of strokes. Embolism is blockage by an embolus (usually a clot) that is swept into an artery in the brain. It accounts for 30% to 35% of stroke cases. Thrombosis and embolism both lead to cessation or marked decrease of the blood supply to part of the brain, and thus to infarction, or tissue death.

The third mechanism is rupture of a blood vessel in or near the brain, which may cause an intracerebral hemorrhage (bleeding within the brain), or a subarachnoid hemorrhage (bleeding over the surface of the brain). Hemorrhages account for 20% to 25% of stroke cases. The authors report that during their 14-year follow-up study, 574 strokes were documented, including 181 hemorrhages, 303 ischemic strokes (264 thrombotic and 39 embolic infarctions), and 90 strokes of undetermined type.

"We observed a significant inverse association between fish intake and risk of stroke, primarily thrombotic stroke, after adjustment for cardiovascular risk factors and selected dietary variables," Iso et al. wrote. "Compared with women who ate fish less than once per month, those with higher intakes of fish had a lower risk of total stroke."

After adjusting for age, smoking, and other cardiovascular risk factors, women who ate fish ...