Familial hypercholesterolemia more common than previously reported

By Will Boggs MD

NEW YORK (Reuters Health) - The prevalence of familial hypercholesterolemia (FH) among U.S. adults is much higher than previously thought, according to results from the National Health and Nutrition Examination Survey (NHANES).

"Our work suggests the prevalence of this profile is twice as common as previously thought, 1 in 250," Dr. Sarah D. de Ferranti from Boston Children's Hospital in Massachusetts, told Reuters Health by email. "Early identification of genetic/familial hypercholesterolemia is extremely important to allow for treatment of these individuals at an early age."

Previous estimates of FH prevalence range from 1 in 500 to 1 in 137, depending on the population's ancestry and the criteria used to define FH.

Dr. de Ferranti and colleagues used NHANES data to estimate the prevalence of FH as defined by a modified version of the Dutch Lipid Clinic criteria, which include low-density lipoprotein (LDL) cholesterol levels, gene defects causative for FH, personal or family history of early atherosclerotic cardiovascular disease, and physical findings associated with high cholesterol.

The overall U.S. prevalence of probable/definite FH is 0.40% (1 in 250). Extrapolation to the U.S. population translates into 834,500 adults at least 20 years of age with probable or definite FH.

FH was more common in obese (1 in 172) than nonobese (1 in 325) individuals, according to the March 15 report in Circulation, and the prevalence was higher among whites, blacks, and other Hispanics (0.40%-0.58%) than among Mexican American and other races (0.24%-0.29%).

At an LDL cholesterol cut point of at least 4.9 mmol/L (189 mg/dL), the prevalence of FH among U.S. adolescents is 0.42%.

"For someone who has FH, a cholesterol level and/or family history consistent with FH, it is extremely important to get early consistent preventive care," Dr. de Ferranti said. "The key is for patients and clinicians to distinguish between mild to moderately high cholesterol that comes on in middle age related to a less than ideal lifestyle and very high cholesterol that has been present since birth, which has allowed the high cholesterol to build up over decades."

"We have very effective medications to lower cholesterol that we believe can reduce heart disease rates in those with FH to the level of people without FH, if taken early enough and with good consistency," she explained. "While diet alone is not enough, following heart healthy habits like getting regular physical activity, keeping your weight in the normal range, avoiding smoking, and watching for other heart disease risk factors like hypertension is still important, even if you have a genetic cholesterol disorder, because you can make your situation worse by adding other risk factors on top of the FH."

"Children in families with early heart disease and/or very high cholesterol should be screened for cholesterol disorders as well," Dr. de Ferranti said.

Dr. Samuel S. Gidding from A.I. DuPont Hospital for Children, Wilmington, Delaware, who coauthored an editorial related to this report, told Reuters Health by email, "These data are limited by the absence of extensive information on family history in the database and, of necessity, genetic confirmation. Nonetheless, they are suggestive of prevalence similar to that reported in other countries and make familial hypercholesterolemia the most common single gene defect condition in the U.S."

"More comprehensive efforts to identify those with familial hypercholesterolemia should be made, as early treatment beginning at about 10 years of age may prevent heart disease later in life," Dr. Gidding said.

Dr. Gerald F. Watts from Royal Perth Hospital, University of Western Australia, Crawley, Australia, who has published extensively about FH, offered Reuters Health this advice by email: "Think of FH more than you do: measure cholesterol; take a family history; consider other family members; treat FH earlier with lifestyle changes and statins; refer difficult cases to specialists."

"Genetic testing will increase accuracy of diagnosis, but is not essential," Dr. Watts said. "USA needs a coordinated screening and care program for FH."

Dr. Stephen R. Daniels, from the University of Colorado School of Medicine, Aurora, told Reuters Health by email, "Because we know that individuals with heterozygous familial hypercholesterolemia are at increased risk of atherosclerotic cardiovascular disease at an early age, and the prevalence indicates that this is a relatively common condition, we should be working harder to identify these individuals and lower their LDL cholesterol levels. This is the main message that clinicians should be getting from this paper."

The Patient-Centered Outcomes Research Institute supported this research. Six coauthors and two commentators reported disclosures.

SOURCE: http://bit.ly/1U4M1ao and http://bit.ly/1M5eMk5

Circulation 2016.

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