Health and Fitness News and Notes

Supplements containing omega-3 fatty acids, the oils abundant in fatty fish, are ineffective for the prevention of heart disease, a large review of randomized trials has found.

The analysis, in JAMA Cardiology, pooled data from 10 randomized trials in people who had cardiovascular disease or were at high risk for it. There were 77,917 people in the trials, 61 percent men, and their average age was 64. Studies lasted, on average, 4.4 years, and the dose of omega-3s ranged from 226 to 1,800 milligrams a day.

No matter how the researchers looked at the data, they could find no association of the supplements with lowered risk for death from heart disease, or with nonfatal heart attacks or other major cardiovascular events.

There was no effect in people with prior coronary heart disease, those with diabetes, people with high lipid levels or people using statins. There was no evidence for an effect in either women or men considered separately.

The American Heart Association recommends supplements for people with coronary artery disease who may not get enough omega-3s by diet alone, but the study provided “no support” for those guidelines, said the senior author, Dr. Robert Clarke, a professor of epidemiology at the University of Oxford.

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 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.”

Besides a flu vaccination, Kwong said, there are other steps to prevent getting the disease, such as frequent hand-washing.

Having migraines increases the risk for cardiovascular diseases, a new study has found.

Using the Danish National Patient Registry, researchers matched 51,032 people with migraines, 71 percent of them women, with 510,320 people in the general population without migraines. The subjects were, on average, age 35 at the start of the study, and researchers followed them for 19 years.

The absolute risk for cardiovascular disease was small, unsurprising in a group this young. Nevertheless, after adjustment for other variables, over the course of the study people with migraines had a 49 percent increased chance of heart attack, and roughly double the risk of stroke. They also had a 59 percent increased risk of a blood clot in their veins. These risks were even higher in the first year after a migraine diagnosis.

The observational study, in The BMJ, found no association of migraine with peripheral artery disease or heart failure.

“We now have accumulating evidence that migraine is a risk factor for cardiovascular disease,” said the lead author, Dr. Kasper Adelborg, a postdoctoral researcher at Aarhus University, who added, “It’s important to find out if the agents that prevent migraine could also reduce the burden of cardiovascular disease.”