Flu shot called major heart attack preventive

Researchers make case for stopping 91,000 deaths


HOUSTON - The inexpensive flu shot might be medicine's most powerful preventive against heart attacks and strokes, topping even cholesterol-lowering drugs in saving tens of thousands of lives per year, according to Houston researchers.

"So cheap and so widely available but so underutilized it's unbelievable," said Dr. Mohammad Madjid, a flu-shot proponent and an assistant professor of medicine in the cardiology division at the University of Texas Medical School at Houston.

Madjid said influenza immunizations could prevent up to 91,000 heart attack and stroke deaths a year, but fewer than 30 percent of people at risk for dying from cardiovascular disease receive the vaccine.

Cardiologists don't routinely recommend them, Madjid said, leaving that job to primary care physicians.

Dr. Paul Glezen, head epidemiologist at Baylor College of Medicine's Influenza Research Center, says cardiologists should take a leading role in advocating flu shots.

"The cardiologist may be the most influential person with people with heart disease," he said.

Madjid is a co-author of an article that appeared yesterday in Circulation, the journal of the American Heart Association, which calls for better adherence to, and possible expansion of, federal flu-shot guidelines.

Those guidelines now recommend the vaccine be administered to all people older than 50 and everyone with cardiovascular disease.

Influenza is thought to trigger heart attacks and strokes by destabilizing fatty deposits clinging to artery walls.

Inflammation caused by the flu can help blood clots form around the fatty deposits, or the infection can cause one of the deposits to break apart, ultimately blocking a blood vessel and setting off a stroke or heart attack.

A growing body of research has shown that flu shots reduce heart attack risk by 50 percent to 67 percent.

Other studies show influenza vaccination could cut stroke risk in half. In comparison, statin drugs, which lower blood cholesterol, reduce cardiovascular disease deaths by 30 percent on average.

The researchers calculated that if 10 million people worldwide began taking cholesterol-lowering drugs today, 50,000 lives would be saved per year.

By contrast, Madjid and his colleagues estimate that flu shots could prevent as many as 91,000 of each year's 729,000 deaths from stroke and heart attack, a number that far exceeds the traditional estimates - 20,000 per year - of flu-related deaths.

Influenza immunization isn't used more widely as a heart attack preventive because of "lack of knowledge," Madjid said.

Madjid said many cardiologists don't know about the connection or consider flu shots something best left to public health experts.

"What keeps people alive is eating the right foods, exercise, a positive outlook and a flu shot," said study co-author Dr. Ward Casscells, a UT-Houston cardiologist known for his research on atherosclerotic plaque, the fatty deposits that lead to thickening and hardening of the arteries.

"The rest of this stuff [statins, angioplasty, stents] is, unfortunately a $50 billion business, but it's not what keeps people alive."

Casscells said he was convinced of the importance of flu shots by patients who told him they had a cold or pneumonia just before a heart attack.

The American Heart Association, the American College of Cardiology and other cardiology groups should formally endorse the Centers for Disease Control and Prevention flu shot recommendations (people over 50 and everyone with heart disease) and target less-affluent groups with lower vaccination rates, Madjid said.

In addition, the UT-Houston researchers believe the CDC and the American Public Health Association should conduct trials to study whether the vaccine can prevent heart attacks in people with "preclinical" or early heart disease, such as patients with stress tests that indicate borderline problems or people with evidence of coronary calcification.

Madjid said he is concerned about minorities who have higher death rates from heart disease and lower rates for vaccinations.

The influenza vaccination rate among whites is 66 percent, among Hispanics 50 percent and among blacks 46 percent.

Madjid suggested that ministers of churches with predominantly minority congregations could help spread the word.

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