Cholesterol levels in U.S. youth have improved from 1999 to 2016, but only half of children and adolescents are in the ideal range and 25 percent are in the clinically high range, according to a Northwestern Medicine study published in JAMA.

The study is the first to report estimated prevalence of high cholesterol in youth in recent years, analyzing nationally representative data from more than 26,000 children and adolescents (ages 6 to 19 years).

“High cholesterol in childhood is one of the key risk factors for developing heart disease later in life,” said first author Amanda Marma Perak, ’09 MD, ’18 MS, ’16 GME, assistant professor of Pediatrics in the Division of Cardiology and a cardiologist at Ann & Robert H. Lurie Children’s Hospital of Chicago. “Although we see favorable trends in all measures of cholesterol in children and adolescents over the years, we still need to work harder to ensure that many more kids have healthy cholesterol levels. We know that high cholesterol is the critical initiator of atherosclerotic plaques in the arteries, and even in childhood it is associated with these changes in the blood vessels that can lead to heart attack in adulthood.”

For children and adolescents, ideal measures include total cholesterol (TC) at less than 170 mg/dL, LDL or “bad” cholesterol at less than 110 mg/dL, and HDL or “good” cholesterol at greater than 45 mg/dL. These levels are associated with better long-term health. All youth should have their cholesterol checked at ages 9 to 11 years and again at 17 to 21 years, according to the latest guidelines from the National Heart, Lung and Blood Institute.

“If a child is found to have borderline-high or high levels of cholesterol, we can usually improve those levels through lifestyle changes, such as healthier diet and increased physical activity,” said Marma Perak, also an assistant professor of Preventive Medicine. “Children are rarely placed on cholesterol-lowering medications like statins.”

The improving cholesterol trends observed in the study are surprising, given that obesity is one of the factors that drives abnormal cholesterol levels, and childhood obesity continues to increase.

“More research is needed to understand the reasons for the favorable cholesterol trends we found,” Marma Perak said. “Some factors that influence cholesterol may be improving, such as decreased trans fats in the food supply. Although more efforts are needed, the fact that cholesterol levels are moving in the right direction warrants some optimism about the future cardiovascular health of our population since cholesterol is such an important driver of cardiovascular disease.”

Donald Lloyd-Jones, MD, ScM, chair and Eileen M. Foell Professor of Preventive Medicine and senior associate dean for Clinical and Translational Research, was the senior author of the study.

The study was supported in part by a National Institutes of Health training grant (T32 HL069771), a National Heart, Lung and Blood Institute career development award (K23 HL145101) and a Pediatric Physician-Scientist Research Award from the Department of Pediatrics at Northwestern University Feinberg School of Medicine.

Research at Ann & Robert H. Lurie Children’s Hospital of Chicago is conducted through the Stanley Manne Children’s Research Institute.