New Practice Guidelines To Be Issued|
Average Blood Pressure Levels On Rise Among American Children/Teenagers
Systolic and diastolic blood pressure levels for children and teenagers
have risen substantially since 1988, according to a new study supported
by the National Heart, Lung, and Blood Institute (NHLBI), part of
the National Institutes of Health. The study links part of the rise
to a concurrent increase in the prevalence of overweight and obesity.
The study "Trends in Blood Pressure Among Children and Adolescents" appears
in the May 5, 2004 issue of The Journal of the American Medical
Association (JAMA). The study was conducted by researchers at Tulane
University in New Orleans, LA, and the NHLBI in Bethesda, MD.
This summer, the NHLBI and the National High Blood Pressure Education
Program, which it coordinates, will release updated clinical practice
guidelines on high blood pressure in children and adolescents. The
guidelines, presented in summary form on May 1, 2004 at the annual
meeting of the Pediatric Academic Societies (PAS) in San Francisco,
include revised blood pressure tables and updated recommendations
for lifestyle and drug therapies.
"The obesity-related rise in blood pressure among American
children is a serious health issue," said NHLBI Acting Director
Dr. Barbara Alving. "We need to take steps to reverse this
trend. One key step is to give physicians tools that can help them
deal with this problem, which is why we're issuing these new guidelines."
"The increases found by the JAMA study in children's average
blood pressures may seem small, but they can have serious consequences,"
said Dr. Jeffrey Cutler, Senior Advisor, NHLBI Division of Epidemiology
and Clinical Applications, and co-author of the JAMA paper. "Previously
published data indicate that, for each 1- to 2-millimeter of mercury
rise in their systolic blood pressure, children face a 10 percent
greater risk of developing hypertension as a young adult."
High blood pressure is a major risk factor for heart disease and
the chief risk factor for stroke.
The new blood pressure trends study in JAMA involved 5,582 children
ages 8-17, who were part of the 1988-94 and 1999-2000 National Health
and Nutrition Examination Surveys (NHANES). In both surveys, the
children were about 50 percent male, 16-17 percent black, and 9-12
percent Mexican-American. The mean age for both groups was just
under 13 years.
In 1988-94, the children's average systolic blood pressure was 104.6
mm Hg and their average diastolic pressure was 58.4 mm Hg. In 1999-2000,
the children's average systolic pressure was 106 mm Hg and their
average diastolic was 61.7 mm Hg.
In 1988-94, 11.7 percent of the children were overweight; in 1999-2000,
16.3 percent were overweight. Overweight is defined by body mass
index (BMI), which is a measure of weight relative to height. Overweight
children and teenagers have a BMI that falls in the 95th percentile
or higher on age- and gender-specific growth charts, compiled by
the Centers for Disease Control and Prevention.
The systolic and diastolic blood pressure increases between the
two surveys were large and occurred for all age and race/ethnic
groups, and both genders. The systolic pressure increased by 1.4
mm Hg and the diastolic by 3.3 mm Hg from 1988-94 to 1999-2000.
Even after adjusting for BMI, systolic and diastolic blood pressures
were 1 and 2.9 mm Hg higher, respectively, in 1999-2000, compared
with 1988-94. This suggests that lifestyle factors other than overweight,
such as physical activity and specific dietary nutrients, were also
involved in the trends.
Further, systolic and diastolic blood pressures increased with age
for all race/ethnic groups and both genders. For children ages 8-12,
yearly systolic and diastolic blood pressure increases were greater
for girls, compared with boys. For adolescents ages 13-17, yearly
blood pressure increases were greater for boys, compared with girls.
The new clinical practice guidelines due for release this summer
reflect new data from the 1999-2000 NHANES. The data have been added
to the childhood blood pressure database and reexamined to develop
revised normative blood pressure tables. The updated tables now
include the 50th, 90th, 95th, and 99th percentiles of blood pressure
by sex, age, and height.
Hypertension in youngsters is based on the range of blood pressures
in healthy children. The new guidelines continue to define normal
blood pressure as the systolic and diastolic blood pressures that
are less than the 90th percentile for that sex, age, and height.
To be consistent with the latest blood pressure guidelines for adults*,
the guidelines for children include a prehypertension category.
Children with a systolic or diastolic pressure equal to or greater
than the 90th percentile but less than the 95th percentile are considered
prehypertensive. Hypertension continues to be defined as a systolic
or diastolic pressure equal to or greater than the 95th percentile.
The new guidelines describe hypertension and prehypertension as
significant health issues in the young due to the marked increase
in the prevalence of overweight children. Overweight and high blood
pressure are components of the insulin resistance syndrome, a combination
of multiple risk factors for cardiovascular disease and type 2 diabetes.
Therefore, the guidelines call for a comprehensive assessment of
cardiovascular risk factors. The new guidelines, noting the association
of high blood pressure and overweight with sleep apnea, also suggest
that a history of sleeping patterns should be obtained in a child
Treatment for children with high blood pressure usually consists
of lifestyle changes, including weight management, physical activity,
and dietary changes. Drug therapy is used if needed. The revised
guidelines incorporate recent research and present updated recommendations
for lifestyle approaches, such as dietary changes for children and
adolescents who have prehypertension as well as hypertension. Revised
drug recommendations include dosage recommendations for many of
the newer drugs studied in recent clinical trials.
"We want to give our children the best possible start in life,"
said Alving. "That means insuring they have a healthy blood
pressure and weight. 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."
To arrange an interview about this study, contact the NHLBI Communications
Office at (301) 496-4236.
Tables from the new clinical practice guidelines on hypertension
in children and adolescents are available at www.nhlbi.nih.gov/guidelines/hypertension/child_tbl.htm.
NHLBI press releases and other materials are available online
* Seventh Report of the Joint National Committee on the Prevention, Detection, Evaluation and Treatment of High Blood Pressure (JNC 7)