Drinking coffee does not appear increase the risk of heart attack, according to a study of older Swedish women, and it may even be protective.

Seveal studies have examined ties between coffee consumption and risk of heart attack, but results have been mixed. Some studies have suggested a harmful effect of coffee consumption on the heart, whereas others have shown no link.

In their study, Dr. Sarah A. Rosner, of Harvard School of Public Health, Boston, Massachusetts, and colleagues prospectively examined the effect of coffee consumption on the risk of heart attack in 32,650 Swedish women between 40 and 74 years of age.

The women were participating in a study initiated between 1987 and 1990. During an average follow-up of 5.1 years, a total of 459 heart attacks occurred. Of these, 391 were nonfatal and 68 were fatal.

In analyses adjusting for possible confounding factors, the team found that women who drank 5 or more cups of java per week had a 32 percent reduced relative risk of having a heart attack compared with women who drank 0 to 4 cups per week, although this did not reach statistical significance.

Overall, there was “a nonsignificant trend toward lower risk with higher consumption levels,” the investigators report.

There are “several plausible biologic mechanisms” by which coffee may reduce risk of heart attack, Rosner’s team explains. “Coffee contains phenolic compounds, which are known antioxidants and may reduce oxidative stress,” they note. Additionally, coffee has been shown to improve the body’s use of insulin and may protect against type 2 diabetes.

SOURCE: American Journal of Epidemiology, February 2007.