Evidence suggests that fish-especially oily fish, a major source of omega-3 fatty acids-may benefit cardiovascular health. However, scant data exists from regions of the world where varying amounts and types of fish are consumed, and it's unknown if the association between fish consumption and cardiovascular disease (CVD) events varies depending on whether a person has existing vascular disease. In a pooled analysis, researchers investigated whether the association between fish intake and CVD and total mortality differs in people who have or don't have vascular disease.

A total of 191,558 people (51,731 had vascular disease; 139,827 were generally healthy) from 58 countries who had been participants in four large prospective studies were studied. The mean age of participants was 54.1 years, and 47.9% were men. The median duration of follow-up was 7.5 years.

The association between fish consumption and major CVD events and death varied significantly, depending on the person's history of CVD. Among people at high risk for or with existing CVD, a fish intake of at least 175 grams per week (approximately two servings) compared with little or no fish intake (50 grams or less per month) was associated with lower risk of major CVD, total mortality, and the composite of death or major CVD after adjustment for known confounders. Fish consumption of 350 grams per week or more led to no apparent further decrease in risk. In people who didn't have vascular disease, there was no significant association between higher fish intake and major CVD, total mortality, or the composite of death or major CVD. Higher fish intake was associated with a lower risk of sudden cardiac death in people at high risk for or with CVD, but not in the general population. Oily fish appeared to have greater benefits.