Many adults under 40 may not need to have routine cholesterol screenings, a new study suggests.
To come to this conclusion, the researchers looked at the real world implications of two conflicting sets of guidelines on cholesterol testing.
One, from the American College of Cardiology/American Heart Association (ACC/AHA), says that all adults older than 20 should have a cholesterol screening. They also suggest a repeat test every four to six years.
The other guidelines come from the U.S. Preventive Services Task Force, a government-funded, independent panel of medical experts. They say many adults can go longer before their first cholesterol test -- until age 35 for men, and age 45 for women.
The exception would be people with a major risk factor for heart problems -- such as high blood pressure, smoking or a family history of early heart disease.
Those patients can start cholesterol testing at age 20, the task force adds.
The new findings support the "more targeted" approach the task force uses, according to lead researcher Dr. Krishna Patel, of Saint Luke's Health System in Kansas City, Mo.
Why? The study, Patel explained, tried to estimate the impact of the two different guidelines in the "real world."
To do that, the researchers used data on 9,600 U.S. adults aged 30 to 49 who were part of a government health study.
The study team found that among nonsmokers with normal blood pressure, very few were at heightened risk of suffering a heart attack in the next 10 years. That means very few would be considered candidates for a cholesterol-lowering statin -- even with elevated LDL (so-called "bad" cholesterol) levels.
"So, screening cholesterol early doesn't bring much actionable information," Patel said. "If we're not going to treat, there's no point in doing it."
The study was published May 15 in the Annals of Internal Medicine.
Others disagreed with Patel's point.
The point of screening younger adults is not so doctors can put them all on statins, said Dr. Neil Stone, one of the authors of the ACC/AHA guidelines.
Instead, there are two central reasons, Stone explained.
One is to spot younger adults who may be heading down a path toward heart disease later in life.
Once they know their LDL is high, they and their doctors can have an "all-important discussion" about diet and lifestyle changes, said Stone, who is also professor of medicine at Northwestern University's Feinberg School of Medicine in Chicago.
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The other reason is to catch cases of familial hypercholesterolemia, a genetic condition that causes very high LDL levels (above 190 mg/dL), he said.
People with the condition have a much higher-than-average risk of heart disease, and often develop it at a young age.
Because of that, the condition should be treated with statins, according to the ACC/AHA.
There is "strong and compelling evidence," Stone said, that catching the condition in younger adults makes a difference.
Dr. Paul Ridker, who wrote an editorial accompanying the study, had a similar view.
"Familial hypercholesterolemia is a common disorder, and it's easy to detect," said Ridker, of Brigham and Women's Hospital in Boston. "Why delay something as simple and inexpensive as a cholesterol test?"
Plus, he said, catching even "run-of-the-mill" high LDL is important.
"Knowing about it early in life can be a good motivator to make lifestyle changes," Ridker said.
What if a young adult has healthy LDL levels? Ridker said he'd be "fine" with that patient forgoing further tests until later in life.
For her part, Patel agreed that a one-time check, to catch familial hypercholesterolemia, is a wise move for young adults. But she questioned the value of repeat testing.
According to Stone, the ACC/AHA guidelines say it's "reasonable" to repeat cholesterol testing every four to six years. "It's not mandatory," he noted.
But people's lives, and heart disease risk factors, change as they move through adulthood, Stone said. So, a periodic cholesterol check can be useful when it's done as part of a "global risk assessment" where doctors look at blood pressure, smoking habits and other major risk factors for heart disease.
Motivating younger adults to get those risk factors under control is critical, according to Stone. "We know it's a big deal if you can have optimal risk factor [control] by age 45 or 50," he said.
In the study, very few people were at elevated risk of heart attack -- as long as they didn't smoke or have high blood pressure. ("Elevated" meant a greater than 5 percent chance of having a heart attack in the next 10 years.)
In the absence of those two risk factors, only 0.09 percent of men younger than 40 were at elevated risk of heart attack. And only 0.04 percent of women younger than 50 were.
But smoking, in particular, changed everything: Among male smokers in their 40s, one-half to three-quarters were at elevated risk of a heart attack.
"Smoking had a huge effect," Patel said. Smokers, she stressed, should "definitely" have their cholesterol tested -- and, more importantly, quit the habit.