A screening program that combines genetic and lab testing could identify 1 million Americans who are at risk of early death from heart disease because they carry a gene that causes high cholesterol, found researchers at the Columbia University Vagelos College of Physicians and Surgeons.
High cholesterol is among the leading causes of heart attacks and strokes and may be caused by modifiable behaviors, such as a high-fat diet and a lack of exercise.
But for nearly one in 250 people, high cholesterol is written in their genes. This inherited high cholesterol is called familial hypercholesterolemia, or FH.
"If we can identify individuals with FH at an earlier time in their lives, then we can intervene and either prevent or delay heart attacks and strokes."
Among people with FH, "bad" cholesterol can reach unhealthy levels even in childhood. When untreated, people with one gene that causes high cholesterol are about 20 times more likely to have a heart attack-and about 10 to 15 years earlier-than the general population.
"Despite the substantial risks and designation of FH as a high priority for genomic screening by the U.S. Centers for Disease Control and Prevention, screening for FH is not standard practice in the United States," says study leader Brandon Bellows, PharmD, assistant professor of medical sciences at Columbia. "Most people learn they have FH in their 50s, around the age when individuals with untreated FH experience their first heart attack, making prevention a challenge."
The new study estimated how different screening programs for adults age 20 and older would perform in the U.S. population. When used alone, clinical screening (cholesterol tests plus personal or family history of heart attack or stroke) and genetic screening could each identify about 650,000 FH cases. When clinical and genetic testing was combined, screening could identify 1.1 million Americans with the disease.
The results were published on May 18 in the Journal of the American Heart Association.
Limited screening may be more practical
"While universal screening programs with genetic testing may be the best way to identify people with FH, it may also be impractical," Bellows says.
The study estimated that strategies such as offering genetic testing to adults with high cholesterol levels (an LDL of 160 milligrams per deciliter or above) or to adults age 20 to 39 years may find more FH cases per 1,000 people screened or may find FH at an earlier age. More studies are needed to determine the long-term costs and benefits of such screening programs and the ideal age at which screening should begin.
"We need to do more to support FH screening programs and educate the public about FH," says Bellows. "If we can identify individuals with FH at an earlier time in their lives, then we can intervene and either prevent or delay heart attacks and strokes. That's what is really important from this research."
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The study is titled "Estimated Yield of Screening for Heterozygous Familial Hypercholesterolemia With and Without Genetic Testing in US Adults."
All authors: Brandon K. Bellows (Columbia); Amit V. Khera (Massachusetts General Hospital and Harvard Medical School); Yiyi Zhang (Columbia); Natalia Ruiz-Negrón (University of Utah); Henry M. Stoddard (Columbia); John B. Wong (Tufts Medical Center); Dhruv S. Kazi (Massachusetts General Hospital, Harvard Medical School, and Beth Israel Deaconess Medical Center), Sarah D. de Ferranti (Harvard Medical School); and Andrew E. Moran (Columbia).
The researchers received funding from the National Institutes of Health (grants 1K08HG010155, 1U01HG011719, and R01HL141823) for this analysis.
The Columbia authors report no conflicts of interest.
