TUESDAY, Aug. 30 (HealthDay News) -- Genes affect hereditary coronary heart disease risk but family lifestyle does not, according to a new study.

While it's long been known that hereditary factors influence this risk, it hasn't been clear whether this is due to genes or unhealthy lifestyle in the family, the Swedish researchers said.

In order to answer that question, the investigators examined the health records of 80,214 adopted men and women in Sweden who were born in 1932 or later and developed coronary heart disease between 1973 and 2008. The researchers also studied the participants' adoptive and biological parents.

Adopted people with at least one biological parent with coronary heart disease had a 40 to 60 percent higher risk of coronary heart disease than people in a control group.

There was no increased risk for people with one or two adoptive parents who had coronary heart disease, the researchers reported in the August issue of the American Heart Journal.

"The results of our studies suggest that the risk of coronary heart disease is not transferred via an unhealthy lifestyle in the family, but rather via the genes," study leader Kristina Sundquist, a professor at the Center for Primary Health Care Research in Malmo, Sweden, said in a journal news release.

"But that does not mean that one's lifestyle is not a factor in one's own risk of developing coronary heart disease," she added.

More information

The U.S. National Heart, Lung, and Blood Institute outlines coronary heart disease risk factors.