MONDAY, April 1, 2013 (HealthDay News) -- More than 80 percent of U.S. teens eat unhealthy diets and many are sedentary, which raises the odds they'll develop heart disease in adulthood, a new study suggests.
Researchers analyzed data on more than 4,600 teenagers, aged 12 to 19, and assessed their health behaviors based on criteria set by the American Heart Association. The poor health habits they uncovered translate into obesity and overweight, which in turn raise risk factors for high blood pressure and other predictors of cardiovascular trouble, the study authors noted.
"Most children are born in a state of ideal cardiovascular health, [but] the poor lifestyles many U.S. children exhibit are leading to a loss of this important asset earlier and earlier in life," said lead investigator Christina Shay, an assistant professor of biostatistics and epidemiology in the College of Public Health at the University of Oklahoma Health Sciences Center in Oklahoma City.
Childhood levels of cardiovascular disease risk factors strongly predict their threat in adulthood, Shay said. And the length of time young people live with elevated risk factors also has an impact on their heart health as adults, she added.
Based on the current findings, the United States may witness "increasing rates of heart attacks and strokes as the current generation of children reach adulthood compared to previous generations that had more favorable risk factors," she said.
The students, who participated in one of two National Health and Nutrition Examination Surveys, are said to represent about 33 million teens nationwide. Their health behaviors were rated as poor, intermediate or ideal.
The heart association says cardiovascular health depends on seven factors: not smoking, maintaining a normal weight, eating a healthy diet, being physically active, and maintaining low blood sugar, blood pressure and cholesterol levels.
The study, published in the April 2 issue of Circulation, found less than 50 percent of U.S. teens had five or more of these healthy heart components.
None of the students met all seven criteria for "ideal" cardiovascular health. Mexican Americans were more likely than whites and blacks to meet five or more ideal cardiovascular health components.
About one-third of males and females had less than ideal body mass index (BMI), a measurement of body fat based on height and weight. And about one-third of males and females had also smoked.
Differences between males and females were also noted. Males did better than females in achieving ideal physical activity levels -- 67 percent compared to 44 percent. But almost one-quarter of males (22 percent) had less than ideal blood pressure compared to 10 percent of females.
Females were also more likely than males to have ideal fasting glucose levels (used to predict diabetes) -- 89 percent versus 74 percent.
Experts say the findings are cause for concern.
"This study provides further emphasis that cardiovascular risk factors and behaviors associated with the development of adult atherosclerosis frequently develop early in life," said Dr. Gregg Fonarow, a spokesman for the American Heart Association and professor of cardiology at the University of California, Los Angeles. Atherosclerosis is more commonly known as hardening of the arteries.
Shay and Fonarow said significant environmental and cultural changes are needed to promote healthier lifestyles for teens in order to improve their cardiovascular health.
"These unfavorable lifestyle habits have likely already led to the high proportion of children in this study that also exhibited elevated levels of cholesterol, blood sugar and blood pressure," Shay said.
Another expert said prevention works.
"As a culture, we take for granted that heart disease will occur often at or after mid-life," said Dr. David Katz, director of the Yale University Prevention Research Center in New Haven, Conn. "Yet the reality is that coronary artery disease need not happen at all, and certainly could be eliminated 80 percent of the time or more by eating healthy, being physically active and not smoking."
The results here show this opportunity is being squandered, Katz said. "Our sons and daughters are missing out on the opportunity and benefits of healthful eating and routine physical activity and so are showing early warning signs of heart disease," he added.
"Rather than eliminating heart disease as we could," he said, "our culture is putting ever younger people at risk."
For more information on heart health, visit the American Heart Association.