Familial hypercholesterolemia is twice as common as thought

A new study shows that familial hypercholesterolemia (FH) affects 1 in 250 American adults—which makes the disorder twice as prevalent in the United States as previous estimates reported, according to results published March 14, 2016 in the journal Circulation. The new study used data from nearly 37,000 adults in the National Health and Nutrition Examination Survey (NHANES).

“It’s more common than we thought, and it’s important to look for it at a young age because someone with FH may have no symptoms until there is serious heart disease,” said the study’s lead author Sarah de Ferranti, MD, MPH, Assistant Professor of Pediatric Cardiology at Harvard Medical School, in Boston, MA.

“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," she said.

This study used data from 36,949 adults who took part in 1999-2012 NHANES, and extrapolated that to the 210 million American adults aged 20 and older. To determine cases of FH, researchers used participants’ low-density lipoprotein (LDL) cholesterol levels as well as personal and family history of premature atherosclerotic cardiovascular disease.

Results showed that FH is equally prevalent in women and men, but varies by race and ethnicity. It occurs in 1 in 211 blacks, 1 in 249 whites, 1 in 414 Mexican Americans, and 1 in 343 among other races, according to estimates from this study.

Prior to this study, the prevalence of FH in the US was unknown. The commonly reported estimate of 1 in 500 adults had originated in selected, non-representative populations.

FH also varies by age and weight. The condition is least common among people in their 20s (1 in 1,557) and most common in people in their 60s (1 in 118). FH is also more prevalent among people with obesity (1 in 172) compared with those who are not obese (1 in 325).

“The fact that FH varies by age and obesity shows that there are other factors at play in raising LDL-cholesterol levels in addition to genetics,” said Dr. de Ferranti, who is also Director of Preventive Cardiology at Boston Children’s Hospital in Massachusetts. She acknowledged that the lack of genetic information in NHANES was a limitation of the study. 

“The next step forward could be to take blood samples from a data set such as NHANES and look for the prevalence of FH genetic mutations and the heart attack rate,” she said.

Familial hypercholesterolemia is a life-shortening disease but, if properly identified, there are safe and effective treatments for it. “If you’re born with FH, you have lifelong exposure to high cholesterol, making your heart attack risk similar to someone decades older,” Dr. de Ferranti said. “If you know that somebody has had an early heart attack in your family, consider asking for everyone to be checked.”