U.S. children’s and teens’ average blood pressure levels have dropped over the past decade, with a commensurate drop in elevated and high blood pressure among those under 18, according to a new study.
“Inconsistent with previous four studies, results of the current study may indicate promising effects of public health improvement on healthy lifestyles and dietary behaviors on blood pressure control in children and adolescents,” reported Dr. Bo Xi of Shandong University, Jinan, China, and associates. “Reduction of daily intakes of energy, carbohydrate, total fat, and total saturated fatty acids among U.S. children and adolescents may help explain the decrease in mean blood pressure levels and prevalence of elevated blood pressure” (Am. J. Hypertens. 2015 July 8 [doi:10.1093/ajh/hpv091]).
The researchers grouped data from the 14,270 children, aged 8-17 years, in the seven National Health and Nutrition Examination Surveys from 1999 to 2012 into three time periods: 1999-2002, 2003-2008, and 2009-2012. They defined high blood pressure as a systolic and/or diastolic blood pressure at the 95th percentile or higher for a child’s sex, age, and height. Elevated blood pressure fell between the 90th and 95th percentile or at least 120/80 mm Hg.
From 1999-2002 to 2009-2012, both average systolic and diastolic blood pressure dropped overall, 0.7 and 4.2 mm Hg, respectively. Diastolic blood pressure dropped for both males and females, for those in the lower (8-12) and higher (13-17) age groups, and across all race/ethnicity groups. Only girls, whites, and those aged 8-12 years saw overall drops in average systolic blood pressure.
From 2009 to 2012, nearly one in 10 children and teens (9.6%) had elevated blood pressure, and 1.6% had high blood pressure. The prevalence of elevated blood pressure and high blood pressure had dropped 2.8 percentage points and 1.3 percentage points, respectively, since 1999-2002. However, teens remained more likely to have elevated blood pressure (odds ratio, 2.62), compared with children, and blacks had higher odds than did whites (OR = 1.39). Girls had half the odds that boys had (OR = 0.5). The trends were similar for high blood pressure.
The total daily calories, carbohydrates, fat, and saturated fatty acids intake among children and teens also decreased from 1999-2002 to 2009-2012, while polyunsaturated fatty acids and dietary fiber intake increased. Sodium, potassium, protein, cholesterol, and caffeine intake did not change during this time, independent of adjustments for body mass index–Z scores. The researchers also found a sodium intake of more than 3,450 mg/d was linked to a higher systolic blood pressure and prevalence of elevated blood pressure, compared with an intake remaining at or below 2,300 mg/d, the recommended daily intake level.
The National Institutes of Health, the Scientific Research Organization Construction Project of Shandong University, and the Research Fund for the Doctoral Program of Higher Education of China supported the study. The authors reported no conflicts of interest.