The average blood pressure for Americans ages 8 to 17 has increased over the past 10 years, meaning that more are putting themselves at risk of cardiovascular disease later in life, according to a report released Tuesday.

Since a previous survey conducted between 1988 and 1994, young Americans’ systolic blood pressure (the top number in a blood pressure reading) has increased by more than 1 point. Diastolic blood pressure (the bottom number) jumped more than 3 points in the same time period, according to the Journal of the American Medical Association report.

Study author Dr. Paul Muntner explained that previous research shows that every increase in systolic blood pressure by 1 to 2 units raises children’s risk of having high blood pressure, or hypertension, as a young adult by 10 percent.

So while a small increase in average blood pressure might not harm kids right away, it may later in life, Muntner noted.

“The results of the current study indicates that we may have a greater burden of clinical hypertension occurring over the next 20 years as these children become adults,” the researcher, based at Tulane University in Louisiana, told Reuters Health.

“It’s that long-term outlook that makes us concerned,” added his co-author, Dr. Jeffrey Cutler of the National Heart, Lung and Blood Institute in Maryland.

Cutler noted that excess pounds, lack of exercise and unhealthy eating are all likely to blame for the increase in average blood pressure in U.S. children and teens.

During the study, the researchers reviewed data collected as part of national surveys conducted during the years 1988 to 1994, and 1999 to 2000.

Average blood pressure in children and teens rose between the two study periods, but the increase was greater in some groups than in others, the authors note. For instance, in the latest survey, average systolic pressure was higher in African-American and Mexican-American boys than in whites.

Muntner explained that most of the racial differences in blood pressure can be attributed to weight, for African-American and Mexican-American children and teens tended to weigh more than whites.

In an interview with Reuters Health, Cutler said that “multiple levels” of interventions are likely needed to curb the trend of rising blood pressure among young Americans. For example, schools, families and communities all need to encourage activity and healthier eating habits among teens and children, he said.

For children and teens who already have higher blood pressures, Muntner suggested that they talk to their doctors about what sustainable lifestyle changes they could make that would enable them to lose weight and exercise more. However, that is often easier said than done, he noted.

“Weight loss among overweight children is difficult, just as it is among adults,” Muntner said.

SOURCE: Journal of the American Medical Association, May 5, 2004.