New Orleans, LA - Systolic and diastolic blood-pressure levels for children and teenagers have been rising steadily since 1988, a new study has found.1 The researchers, led by Dr Paul Muntner (Tulane University, New Orleans, LA), link part of the rise in BP to the increasing prevalence of weight gain and obesity. "Although this finding represents little in the way of immediate risk, we can expect to see higher rates of clinical hypertension over time and, in the long term, increasing rates of heart disease and stroke," Muntnertold heartwire.

The study appears in the May 5, 2004 issue of the Journal of the American Medical Association.

In this cross-sectional study, the researchers examined trends in systolic and diastolic blood pressure among children and adolescents between 1988 and 2000. They used nationally representative samples of children and teens aged 8 to 17 years from two National Health and Nutrition Examination Surveys (NHANES):

NHANES III 1988 to 1994 (n=3496).

NHANES 1999 to 2000 (n=2086).

Muntner and colleagues observed that from 1988 to 1994, the children's average systolic blood pressure was 104.6 mm Hg and their average diastolic pressure was 58.4 mm Hg. In the 1999-2000 period, those figures jumped to 106 mm Hg and 61.7 mm Hg (an average increase of 1.4 mm Hg for systolic blood pressure and 3.3 mm Hg for diastolic).

"The increase in diastolic blood pressure among children and adolescents from NHANES III to NHANES 1999 to 2000 was especially large," the researchers write. "Although we cannot rule out random measurement errors, it seems unlikely that any random errors would account for the large increase in diastolic blood pressure observed."

Significant increases were found in all subgroups for diastolic blood pressure and in most subgroups for systolic. "We were surprised by the consistency of the findings across subgroups," Muntnersaid. "Blood pressure increased in boys, girls, Mexican Americans, black Americans, and so forth."

"The increases found by the study in children's average blood pressures may seem small, but they can have serious consequences," coauthor Dr Jeffrey Cutler (National Heart, Lung, and Blood Institute, Bethesda, MD) said in a news release. "Previously published data indicate that for each 1- to 2-mm-Hg rise in their systolic blood pressure, children face a 10% greater risk of developing hypertension as young adults."

Muntner and colleagues point out several limitations to their study, including its cross-sectional design. They write that although estimates of blood-pressure levels were based on an average of three blood-pressure measurements during a single visit, a more precise approximation could have been obtained by averaging multiple blood-pressure measurements during several visits.

The researchers also note that while they were able to assess the potential impact that an increase in body-mass index might have had on blood pressure levels, data on trends for several other variables relevant to children and adolescents were not available from both surveys.

They conclude that confirmation of the trends observed in the current study is needed. And factors that have resulted in higher blood-pressure levels among children and adolescents in the US also need to be identified.

This summer, the National Heart, Lung, and Blood Institute will release updated clinical-practice guidelines on high blood pressure in children and adolescents. The guidelines will include revised blood-pressure tables and updated recommendations for lifestyle and drug therapies.

"We want to give our children the best possible start in life. That means ensuring they have a healthy blood pressure and weight," Dr Barbara Alving (National Heart, Lung, and Blood Institute) said in a news release. "We need to teach them to be physically active and to follow a heart-healthy eating plan. Otherwise, we may be giving them an early start on heart disease."