The condition is called heterozygous familial hypercholesterolemia. It's believed to affect about 1.5 million people in the United States, the researchers said.
The genes linked to this condition prevent the liver from removing LDL (low-density lipoprotein) cholesterol from the blood. This allows the bad cholesterol to build up. Doctors suspect this familial condition when LDL levels are above 190 milligrams per deciliter (mg/dL), the study authors explained.
The researchers reviewed data from six groups of people involved in previous studies. Compared to people with average LDL cholesterol levels (less than 130 mg/dL), those with familial hypercholesterolemia had a five times higher risk for heart disease.
Those with genetically inherited high cholesterol were also more likely to have diseases caused by hardening of the arteries, including earlier development of heart disease -- up to 20 years earlier in men and 30 years earlier in women, the research revealed.
Even when the researchers included other risk factors for heart disease in their analysis, the risks were still higher for those with the genetic cholesterol disorder.
The findings may help doctors explain the risks of familial hypercholesterolemia more clearly to patients. That's important because the disorder can be treated with cholesterol-lowering drugs to decrease the risks for coronary heart disease and stroke, the investigators said.
"Clinician-patient discussions about guideline-supported therapies can be informed by this data," according to the study authors, who were led by Dr. Donald Lloyd-Jones at Northwestern University in Chicago.
Using the data, doctors could present certain scenarios to their patients. For example: if a 25-year-old woman with newly diagnosed familial hypercholesterolemia leaves her cholesterol untreated, her risk of coronary heart disease death or nonfatal heart attack would be comparable to that of a 55-year-old woman, the researchers said.
"Such an analogy, paired with counseling about how to improve risk, may motivate behavioral changes as well as adoption of and adherence to evidence-based medications," the study authors said.
The findings were published June 29 in the journal Circulation.More information
The U.S. National Human Genome Research Institute has more on familial hypercholesterolemia.
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