There are conflicting guidelines regarding when to screen cholesterol levels in young adults. A new study aims to clarify at what age asymptomatic individuals should be screened to calculate their elevated risk of developing atherosclerotic cardiovascular disease.
When there are conflicting guidelines published by different organizations, which one should providers follow?
The 2013 guidelines from the American College of Cardiology and American Heart Association (ACC/AHA) recommend an initial lipid panel for all adults older than 20 years. Meanwhile, the United States Preventive Services Task Force (USPSTF) recommends an initial screening at age 35 for men and age 45 for women. USPSTF only recommends screening earlier if there are any traditional risk factors for atherosclerosis present.
So which approach should be used? A new study in Annals of Internal Medicine described the prevalence of elevated atherosclerotic cardiovascular disease (ASCVD) risk among adults younger than age 50 who do not have diabetes in order to help determine which guidelines to follow. Asymptomatic individuals at risk of ASCVD can pursue lifestyle interventions or medical therapy to reduce their risk of cardiovascular disease, myocardial infarction, and stroke, but in order to identify these individuals, they need to be screened for dyslipidemia.
The researchers studied more than 9600 participants between the ages of 30 and 49 who had not been diagnosed with ASCVD or diabetes. They used the 2013 ACC/AHA ASCVD risk calculator to estimate 10-year ASCVD risk for these participants, who were subdivided by age, sex, and history of smoking and hypertension.
Only 9.1% of participants were estimated to have a 10-year ASCVD risk greater than 5%, which was considered an elevated risk. The percentage with an elevated risk varied widely by subgroups. For instance, nonsmoking, nonhypertensive women younger than age 50 had a 0.04% prevalence of elevated risk. The proportion of nonsmoking, nonhypertensive men younger than age 40 at elevated risk was 0.09%.
They found that smokers at every age had the highest prevalence of elevated risk. Male smokers had a prevalence of elevated risk that ranged from 8.4% between the ages of 30 and 34 to 75.9% between the ages of 45 and 49. Female smokers had a prevalence of elevated risk that ranged from 19.5% between the ages of 30 and 34 to 18.5% between the ages of 45 and 49.
Given these findings, the researchers recommend using the USPSTF’s more targeted approach over the ACC/AHA approach of general screening. They added that screening for asymptomatic individuals should begin at age 40 for men and age 50 for women.
In an accompanying editorial, Paul M. Ridker, MD, MPH, and Nancy R. Cook, ScD, both of Brigham & Women’s Hospital, argue for diagnosis as early as possible.
“We disagree with the USPSTF recommendation to delay lipid screening until mid-adulthood simply because clinical trial evidence is not available in younger persons,” they wrote. “Rather, we believe that at least 1-time LDL-C [low-density lipoprotein cholesterol] screening should be universally recommended for all patients in their late teen or early adult years.”