Cardiology Bernard Rosner
Elevated BP increasing among children, adolescents
July 15, 2013
Risk for elevated BP increased 27% from 1998-1994 to 1999-2008 among children aged 8 to 17 years, according to new research in Hypertension.
Elevated BMI, larger waist circumference and excess sodium intake may be associated with the increase in elevated BP, researchers said.
The study focused on data from a population-based sample of 3,248 children in the National Health and Nutrition Examination Survey (NHANES) III in 1988-1994 compared with 8,388 children in the NHANES from 1999-2008. The main outcome measure was elevated BP, defined as systolic/diastolic BP ≥90th percentile or ≥120/80 mm Hg. Researchers accounted for differences between the two groups in age, sex, race/ethnicity, BMI, waistline and sodium intake.
According to results, the prevalence of elevated BP increased in both boys (15.8% to 19.2%; P=.057) and girls (8.2% to 12.6%; P=.007) from NHANES III to NHANES 1999-2008. Boys were more likely to have elevated BP, but the rate increased more markedly in girls during the study period, according to a press release. Black children had a 28% higher risk for elevated BP compared with non-Hispanic white children.
Mean systolic BP increased in both boys (106.1 mm Hg vs. 107.8 mm Hg; P=.001) and girls (102.3 mm Hg vs. 104.9 mm Hg; P<.001). However, mean diastolic BP increased significantly in girls (57 mm Hg vs. 59 mm Hg; P=.003), but not in boys (57.7 mm Hg vs. 56.7 mm Hg; P=.13).
The researchers reported an independent association between prevalence of elevated BP with BMI (OR=2.00), waist circumference (OR=2.14) and sodium intake (OR=1.36).
More children were overweight in the later NHANES and both sexes, especially girls, had a larger waist circumference. Further,children whose BMI or waist circumference were in the top 25% for their age group were about twice as likely to have elevated BP as children with measurements in the bottom 25%, according to the release.
In both NHANES studies, children with the greatest sodium intake were 36% more likely to have elevated BP compared with children with the lowest intake. More than 80% of children in the studies had a daily intake >2,300 mg; however, fewer children in NHANES 1999-2008 had an intake >3,450 mg. The researchers found an association between mean systolic BP, not diastolic BP, and increased sodium intake in the children.
“Largely because of secular changes in the food supply, dietary patterns and dependence on processed foods, dietary sodium intake has increased in the US population of children as well as adults. The findings in this report demonstrate an association between high sodium intake and elevated BP in childhood and provide support to an Institute of Medicine Report on Strategies to Reduce Na Intake in the United States,” Bernard Rosner, PhD, professor of medicine at Harvard Medical School, and colleagues wrote in the study.
Although the researchers noted “elevated” BP readings, the children could not be diagnosed as hypertensive because NHANES does not have repeated BP measurements over time, according to the release.