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The incidence of elevated blood pressure in children has risen with increased salt intake over the past 20 years, researchers found.
Compared with data from the National Health and Nutrition Examination Survey (NHANES) III from 1988 to 1994, prevalence of elevated blood pressure in children rose in boys (from 15.8% to 19.2%) and rose significantly in girls (from 8.2% to 12.6%) in NHANES 1999-2008, according to Bernard Rosner, PhD, of Harvard Medical School in Boston, and colleagues.
Action Points
- Elevated blood pressure prevalence has increased in children.
- Note that the increase in blood pressure appears to be associated with increased salt intake, with some differences between boys and girls.
In a comparison of the highest and lowest quintiles of salt consumption, increased salt intake was significantly associated with elevated systolic blood pressure (beta=1.25, P=0.034), but not diastolic blood pressure, they wrote in the journal Hypertension.
It is well established that salt intake and obesity rates are climbing nationally. Although prior research has shown associations between elevated body mass index (BMI) and salt consumption with hypertension and prehypertension in adults, the same associations have not been demonstrated in children. Attempts at this research have been limited by small sample sizes of hypertension prevalence.
The authors studied associations between elevated blood pressure and risk factors through data reported in NHANES III on 3,248 children and teens, compared with data from the continuous NHANES from 1999 to 2008 with a population of 8,388 children and teens.
Participants were ages 8 to 17 and had one or more systolic blood pressure and one diastolic blood pressure measures taken. Data were also taken on BMI and self-reported ethnicity.
Sodium intake was adjusted for total caloric intake and divided into quintiles.
Between the NHANES III and continuous NHANES, mean weight and BMI increased significantly for boys and girls (P≤0.016 and P<0.001, respectively). Also, the percentage of overweight children -- at or above the 85th percentile for weight -- also significantly rose (P<0.001).
Similarly, mean systolic blood pressure significantly increased over the course of the study:
- Boys: 106.1 mm Hg versus 107.8 mm Hg (P=0.001)
- Girls: 102.3 mm Hg versus 104.9 mm Hg (P<0.001)
Mean diastolic blood pressure rose significantly in girls (57 mm Hg versus 59 mm Hg, P=0.003), but not for boys.
Prevalence of elevated blood pressure was significantly higher in girls (P=0.007) and approached significance in boys (P=0.057).
Increased blood pressure was significantly associated with elevated salt intake (P=0.038 for trend), BMI, and waist circumference.
"As with adults, the average dietary salt intake of children exceeds nutritional needs, is well above recommended levels, and has been progressively increasing," the authors noted.
They added that the odds of elevated blood pressure in children rose "an estimated 27% between NHANES III and NHANES 1999-2008," and that the odds of an increase among those with the highest quartile of salt intake rose by 36%.
They also noted that the study was limited by a single 24-hour recall of dietary intake, absence of a 24-hour urinalysis to confirm intake, low power to measure low salt intake, and lack of measure of physical activity for all age groups in the NHANES reporting.
From the American Heart Association:
Disclosures
The study was supported by the NIH.
The authors declared no conflicts of interest.
Primary Source
Hypertension
Rosner B, et al "Childhood blood pressure trends and risk factors for high blood pressure" Hypertension 2013; DOI: 10.1161/hypertensionaha.111.00831.