The number of people with familial hypercholesterolemia (FH) or genetically acquired high cholesterol levels may be twice as common in the United States than previously thought, according to a new study.

The condition leads to severely elevated cholesterol since birth and emerges as a leading factor for early heart attack. The researchers warned that people with FH could show no symptom until the onset of a serious heart condition.
Yet someone with this genetically inherited condition has a heart attack risk similar to someone who is decades older.

"A common story might be someone who develops chest pain or has a heart attack in their 30s or 40s – even though they look healthy, eat well, and are thin and fit," says Dr. Sarah de Ferranti, lead author and an assistant professor at Harvard.

The researchers pulled up data of more than 36,000 U.S. adults who were part of a national health and nutrition survey from 1999 to 2012. They then projected data for the 201 million Americans aged 20 and above.

They found that genetically inherited high cholesterol rates afflicted about 834,500 Americans, which translated to one in every 250 adults. Men and women appeared to be affected equally.

However, racial differences are present in the numbers, with one in 249 whites, one in 211 blacks, and one in 414 Mexican-Americans affected by the condition. Research based outside the U.S. estimates that the genetic disorder affects one in 500 adults.

An analysis of the data, too, showed that FH becomes more prevalent with aging and obesity. For instance, it affects 1,557 individuals in their 20s, which balloons to 1 in 118 among those who are in their 60s. This showed that it’s not just genetics that potentially raises LDL or bad cholesterol, de Ferranti says.

With early detection, statin drugs and other treatments can be employed to reduce LDL cholesterol levels as well as heart disease risk. LDL is deemed “bad” in that contributes to the buildup of plaque in the arteries.

Other risk factors should also be controlled among FH patients, including smoking, sedentary lifestyle, poor diet, and weight gain.

In a statement in the same journal issue, the American Heart Association called for a research agenda to tackle this health issue that is “underdiagnosed and undertreated” globally.

The findings were discussed in the journal Circulation of the AHA.

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