Having the flu substantially increases the risk for heart attack, a carefully designed study published in The New England Journal of Medicine has found.
Over a period of seven years, Canadian researchers identified 364 heart attacks in people age 35 and older who had been hospitalized one year before or after they had had the flu. There were 20 heart attacks during seven days after a diagnosis of flu, and 344 during the rest of the year.
The researchers calculate that the risk of a heart attack in the week after getting the flu was more than six times as high as the risk in any other week, and that other kinds of viral respiratory infection tripled the risk for heart attack.
“Infections cause inflammation,” said the lead author, Dr. Jeffrey C. Kwong, a senior scientist at the Institute for Clinical Evaluative Sciences in Toronto, “and that can cause clotting in vessels that serve the heart. In someone already at high risk, this can push them over.”
Dr. Kwong said that the first defense against the flu is vaccination, but that “there are other things you can do. Wash your hands frequently, stay away from sick people if possible, stay at home if you’re sick so you don’t infect others.”