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TUESDAY, Aug. 19 (HealthDayNews) - All those things doctors have been telling you about risk factors and heart disease are really true, according to two major reviews of cumulative research.
Looking at the records of almost 400,000 people involved in three major studies, researchers at Northwestern University report that just about everyone who had a heart attack or "major coronary event" had at least one of four well-established risk factors: high cholesterol, high blood pressure, cigarette smoking or diabetes.
And analysis of data on more than 122,000 patients in 14 international trials shows essentially the same relationship, cardiologists at Indiana Heart Physicians report.
Because the American Heart Association and other organizations have been pounding home the message about the dangers of these risk factors, why are the findings, reported in the Aug. 20 issue of the Journal of the American Medical Association, such a big deal?
Because "a lot of people out there have been saying you can have CHD [coronary heart disease] in the absence of these risk factors," says Alan R. Dyer, a professor at Northwestern's Feinberg School of Medicine and a member of one research team.
Papers have been published in medical journals saying that up to 50 percent of coronary events can occur in people who have none of these risk factors, he adds. This report is being published "to dispel that notion," he says.
The numbers provide an easy refutation. In the Chicago Heart Detection Project in Industry, the Multiple Risk Factor Intervention Trial and the Framingham Heart Study, anywhere from 87 percent to 100 percent of the people who died of heart disease had at least one of the risk factors, the Northwestern researchers say: -blood cholesterol 240 or higher, blood pressure of 140/90 or higher, diabetes or cigarette smoking.
In the 14 international studies examined by Dr. Umesh N. Khot and colleagues, 84.6 percent of women and 80.6 percent of men with coronary heart disease also had at least one of the risk factors.
"Smoking particularly plays a major role in the development of premature heart disease," says Khot, who did the study while at the Cleveland Clinic Foundation and is now with Indiana Heart Physicians.
And there is a risk factor beneath the other three factors, Khot notes--obesity, which contributes to diabetes, high blood cholesterol and high blood pressure.
Like Dyer, Khot is at a loss to explain why so many ordinary people and physicians deprecate the role of the four risk factors. "For some reason, it is still a widespread belief among patients and some clinicians," Khot says.
For both the public and doctors, the lesson of these studies is clear, Dyer adds: "We have to focus on these risk factors when we try to reduce the risk of coronary heart disease."
More information
An overview of coronary risk factors is given by the American Heart Association or the Texas Heart Institute.
