Adolescents' high levels of poor health behaviors and unfavorable cardiovascular risk factors may increase their chances of heart disease as adults, according to new research in the American Heart Association journal Circulation.

Researchers estimated the current state of cardiovascular health of U.S. adolescents based on the seven cardiovascular health components defined in the American Heart Association's 2020 impact goals, which include both health behaviors and factors: blood pressure, total cholesterol, body mass index (BMI), blood glucose, healthy diet, physical activity and smoking. The 4,673 adolescents were 12-to 19-years-old and represented about 33.2 million adolescents nationally.

The participants were part of the National Health and Nutrition Surveys and were equally divided between males and females of all major ethnic groups. The healthy diet score (based on levels of fruits and vegetables, fish, whole-grains, salt and sugar-sweetened beverage intake recommended by the American Heart Association) was the least favorable measure for both boys and girls across ethnic groups — with more than 80 percent rated as having a poor diet, researchers said.

"The far less-than-optimal physical activity levels and dietary intake of current U.S. teenagers, is translating into obesity and overweight that, in turn, is likely influencing worsening rates of high blood pressure, high cholesterol and blood glucose at these young ages," said Christina M. Shay, Ph.D., M.A., study lead author and assistant professor of biostatistics and epidemiology in the College of Public Health at the University of Oklahoma Health Sciences Center in Oklahoma City.

They also found:

• Less than 50 percent of the adolescents had five or more acceptable levels of the health factors (45 percent boys and 50 percent girls).
• Less than 1 percent of boys and girls reached ideal healthy diet levels.
• Forty-four percent of the girls and 67 percent of the boys reached ideal physical activity levels.
• Two-thirds of adolescents had ideal BMI levels, 67 percent for girls compared to 66 percent for boys.
• One-third of adolescents had total cholesterol levels in intermediate or poor ranges.

One encouraging finding is that the majority of boys and girls had never smoked a cigarette or didn't try to smoke one within the past 30 days of two interviews during the five-year study.

"The status of heart health during childhood has been shown to be a strong predictor of heart health in adulthood," Shay said. " Members of the medical and scientific community, parents, teachers and legislators all need to focus their efforts on the prevention and improvement of all aspects of cardiovascular health – particularly optimal physical activity levels and diet — as early in life as possible, beginning at birth."

Co-authors are Hongyan Ning, M.D., M.S.; Stephen R. Daniels, M.D., Ph.D.; Cherie R. Rooks, Ph.D., R.D.; Samuel S. Gidding, M.D.; and Donald M. Lloyd-Jones, M.D., Sc.M. Author disclosures are on the manuscript.

The National Heart, Lung, and Blood Institute funded the study.