The risk of elevated blood pressure among children and adolescents rose 27% during a recent 13-year period, according to a study.
Higher body mass, larger waistlines and excess sodium consumption may be the reasons for the elevated blood pressure readings, researchers reported in a study published July 15 on the website of the journal Hypertension.
“High blood pressure is dangerous in part because many people dont know they have it,” Bernard Rosner, PhD, the lead author of the study and a professor of medicine at Harvard Medical School, said in a news release. “Its a very sneaky thing. Blood pressure has to be measured regularly to keep on top of it.”
In adults ages 20 and older, blood pressure should normally be less than 120/80 mm Hg. However, among children and teens blood pressure norms vary according to age, sex and height.
While the researchers noted “elevated” readings, the children could not be called hypertensive because blood pressure readings must be high three times consecutively for an official diagnosis.
The researchers compared more than 3,200 children ages 8-17 in the National Health and Nutrition Examination Survey III in 1988-1994 to more than 8,300 in NHANES in 1999-2008. They accounted for differences between the two groups in age, sex, race/ethnicity, body mass, waistline and sodium intake.
They found boys were more likely to have elevated blood pressure, but the rate increased more markedly in girls from the first study to the second. More children were overweight in the second study, and both sexes, especially girls, had bigger waistlines. African-American children had a 28% higher risk of elevated blood pressure than non-Hispanic white children.
Children whose body mass or waistline measurements were in the top 25% for their age group were about twice as likely to have elevated blood pressure as children with measurements in the bottom 25%. Children with the greatest sodium intake were 36% more likely than those with the lowest intake to have elevated blood pressure.
More than 80% of children in both studies had a daily sodium intake above 2,300 milligrams, while fewer children in the later study had an intake above 3,450 milligrams.
“Everyone expects sodium intake will continue to go up,” Rosner said. “It seems theres been a little bit of listening to dietary recommendations, but not a lot.”
Americans eat an average 3,400 milligrams of sodium daily — more than twice the 1,500 or less that the American Heart Association recommends. Two-thirds of sodium intake is from store-bought foods and a quarter from restaurant offerings.
Studies have linked excessive sodium in the diet to hypertension, and have suggested that reducing sodium intake in children and adolescents can lower average systolic blood pressure by 1.2 mm Hg and average diastolic pressure by 1.3 mm Hg.
Read the study abstract: http://hyper.ahajournals.org/content/early/2013/07/15/HYPERTENSIONAHA.111.00831.abstract.