(CBS/AP) Half the nation's overweight teens risk heart attacks and other cardiovascular problems because they have unhealthy blood pressure, cholesterol or blood sugar levels, a new government study finds.

And an even larger proportion of obese adolescents have such a risk, according to the alarming new statistics.

"What this is saying, unfortunately, is that we're losing the battle early with many kids," said Dr. Stephen Daniels, a University of Colorado School of Medicine expert who was not involved in the study.

Daniels said these results are not good, since people can keep their risk of heart disease very low if they reach age 45 or 50 at normal weight and with normal blood pressure, normal cholesterol and no diabetes. The study was released Monday in the journal Pediatrics.

For the study, researchers from the Centers for Disease Control and Prevention focused on 3,383 adolescents ages 12 through 19, who were part of an intensive National Health and Nutrition Examination Survey (NHANES) that involves interviewing, weighing, measuring and performing medical tests on people across the country.

Overall the study found that 50 percent of overweight youths and 60 percent of obese youths had at least one risk factor for future heart disease. But normal-weight kids weren't in the clear - 37 percent had at least one risk factor and could face increased chances for heart trouble as adults, the study suggests.

The study showed that the percentage of adolescents who were diagnosed with diabetes or pre-diabetes rose dramatically, from 9 percent to 21 percent. Pre-diabetics have higher than normal blood sugar levels, but not high enough to count as diabetes.

The ongoing CDC study is considered a gold standard for looking at national health trends, said Dr. William Mahle, an Emory University pediatric cardiologist.