News Release

Higher childhood blood pressure may be linked to obesity epidemic

American Heart Association meeting report

Peer-Reviewed Publication

American Heart Association

MIAMI, March 6 – Researchers have found an unexpected increase in the number of children with high blood pressure, and say the growing rate of obesity may be the culprit, according to a study presented today at the American Heart Association's 43rd Annual Conference on Cardiovascular Disease Epidemiology and Prevention.

"Children and adolescents from this survey showed increases in systolic blood pressure compared to what we would have expected based on previous studies of North-American youth," says lead investigator Gilles Paradis, M.D., associate professor at McGill University School of Medicine in Montreal, Canada. "Our results suggest that this increase in systolic pressure is related to the obesity epidemic in children and adolescents."

Systolic blood pressure is the top number in a blood pressure measurement. Diastolic pressure is the bottom number. High blood pressure (hypertension) is defined in an adult as a systolic pressure of 140 millimeters of mercury (mm Hg) or higher and/or a diastolic pressure of 90 mm Hg or higher. Determining normal blood pressure in children is based on their height as well as their age. In children ages 6–12, up to 125/80 mm Hg is considered normal. For youth ages 12–15, 126/78 mm Hg is normal, and for ages 16–18, 132/82 mm Hg is normal. High blood pressure directly increases the risk of coronary heart disease (which leads to heart attack) and stroke, especially along with other risk factors.

Obese children are known to have higher blood pressure. Paradis and colleagues wanted to further examine this issue, recognizing that the long-term consequences of excess body fat may be particularly important when starting at such a young age.

"Schools, parents, health professionals, and policy-makers need to understand that the gravity of the obesity epidemic requires urgent and massive prevention efforts targeted at getting kids to become physically active as well as to eat a healthy diet, promoting optimal growth but not excessive caloric intake. Obesity is the No. 1 dietary disorder in North America. If this were an infectious disease, it would be deemed a public health catastrophe and authorities would be performing widespread vaccinations," Paradis says.

In 1999, the researchers conducted a school-based, multistage, cluster sampling survey of 4,500 youth ages 9, 13, and 16. The children were sampled from a Department of Education list that includes all children and adolescents who attend school in Quebec.

Researchers gathered lifestyle and socio-demographic variables using an age-appropriate questionnaire. They measured the youth's height, weight, blood pressure, and body fat. Body mass index was calculated by a height-to-weight ratio.

Three consecutive blood pressure measures were obtained on the right arm in subjects seated and at rest for at least five minutes. The average of the last two measures was used in the analyses.

Blood pressure was recorded for 3,589 youth. Systolic pressures were more elevated than expected for all age and gender groups, but more so for 13- and 16-year-olds and for boys. Average blood pressures were 103/57 mm Hg for 9-year-olds, 112/59 mm Hg for 13-year-olds, and 119/62 mm Hg for 16-year-olds. Height-adjusted elevated systolic pressure was found in 4.4 percent of 9-year-olds, 16.7 percent of 13-year-olds, and 19.7 percent of 16-year-olds.

Average systolic blood pressure rose with increasing BMI categories in all age and gender groups. Diastolic blood pressure did not increase.

"If our results are confirmed by other investigators, there could be important public health implications," Paradis says. "These children will be tomorrow's hypertensive adults. If these levels of blood pressure persist, the number of people with hypertension could increase substantially over the next decades, with subsequent increases in hypertension-related illnesses."

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Co-authors are Marie Lambert, M.D.; Jennifer O'Loughlin, Ph.D.; Edgar Delvin, Ph.D.; Emile Levy, Ph.D.; Claudette Lavallee, M.S.; Jacinthe Aubin, M.S.; and James A. Hanley, Ph.D.

CONTACT:
For information March 5-8 call
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