Pediatrics

Katherine J. Overwyk, MPH, on Sodium Intake and Elevated BP in Children

A new study using data from the National Health and Nutrition Examination Survey, 2003 to 2016, revealed surprising results about sodium intake and elevated blood pressure (BP) among children and adolescents (i.e., youths) in the United States.1 Corresponding author Katherine J. Overwyk, MPH, answered our questions about this study and the nutritional trends among today’s youth.

Ms Overwyk is a sodium data analyst contracting for the Division for Heart Disease and Stroke Prevention at the National Center for Chronic Disease Prevention and Health Promotion at the Centers for Disease Control and Prevention in Atlanta, Georgia.

CARDIOLOGY CONSULTANT: What is the trend among children and adolescents regarding BP and sodium intake?

Katherine Overwyk: We observed a significant decline in the proportion of children and adolescents with hypertension (6.6% to 4.9%) and with elevated BP or hypertension (16.2% to 13.3%) from 2003-2004 to 2015-2016. Similarly, we observed a concurrent but slight reduction (<250 mg/day over 14 years) in mean usual population sodium intake over the same time period. Participants were classified according to their BP percentiles for age, sex, and height and then as having hypertension, elevated BP, or normal BP using the new percentile tables and definitions for BP in the 2017 American Academy of Pediatrics (AAP) clinical practice guidelines.2 For children and adolescents aged 8 to 17 years, elevated BP was defined as BP in greater than or equal to the 90th percentile but less than the 95th percentile or systolic BP of greater than or equal to 120 mmHg but less than the 95th percentile; hypertension was defined as BP greater than or equal to the 95th percentile, BP at greater than or equal to 130/80 mm Hg, or reported antihypertensive medication use (available for adolescents aged 16-17 years). To coincide with previous reports, we combined participants classified as having elevated BP or hypertension into one group.

CARDIO CON: Did you find that sodium intake affected secular changes in BP among this population?

KO: In this study, the temporal decline in BP was not correlated with the decline in usual sodium intake among children and adolescents, potentially due to the small decline in sodium intake (on average, about 35 mg every two years or less than 250 mg per day over the 14-year period). In our study, a 1000 mg/d reduction in sodium intake was associated with a 20% lower risk of elevated BP or hypertension. Thus, about 4 times the reduction in sodium intake observed over the 14 years may be required to further lower the prevalence of elevated BP or hypertension in this population.

CARDIO CON: Did the 2017 guidelines play a role in this trend? That is to say, did the lower hypertension threshold affect your results?

KO: Similar to our results using criteria from the 2017 AAP clinical practice guidelines,2 declines were also observed over the last 14 years using the former 2004 NIH/NHLBI hypertension guidelines.3 Using the former criteria, the prevalence of elevated BP or hypertension declined from 14.2% in 2003-2004 to 10.7% in 2015-2016, as did hypertension from 3.9% in 2003-2004 to 2.2% in 2015-2016. Our results are consistent with published trends in BP, classified using the 2004 NIH/NHLBI hypertension guidelines, through 2012.

CARDIO CON: How might these findings affect clinical practice or how BP is managed among youths?

KO: Roughly 1 in 8 youths has elevated BP or hypertension. Early detection and intervention of hypertension is important, as increased BP in childhood is associated with increased risk for hypertension in adulthood. The 2017 AAP clinical practice guidelines recommend routine BP measurements during wellness visits starting at 3 years of age and lifestyle interventions if the BP reading is elevated. By diagnosing elevated BP early, pediatricians/primary care physicians can work with youths and their families to establish healthy habits that can reach the entire family.

To improve BP, it’s important for youths to maintain a healthy weight, eat nutritious foods (including foods low in sodium), and be physically active. Evidence from this study indicates that youths consume about 3200 mg/d of sodium (equivalent to about 1.5 teaspoons of salt per day from foods and beverages, excluding salt added at the table). More efforts are needed to lower sodium intake, given that higher sodium intake is associated with higher BP among US youths. Clinicians can counsel parents about choosing low-sodium foods and following a healthy dietary eating plan such as the Dietary Approaches to Stop Hypertension (DASH) diet.

CARDIO CON: What is the key take-home message for practicing cardiologists and pediatricians?

KO: Over the last 14 years, declines in BP and sodium intake were observed among US children and adolescents. Yet 1 in 8 US youths has elevated BP or hypertension, and youths consume more than 3200 mg/d of sodium. To reduce chronic disease risk, the National Academy of Medicine recommends reducing sodium intake if above 2300 mg/d for youths aged 14 to 18 years, and if above 1500 to 1800 mg/d for those aged 8 to 13 years.

Clinicians can enhance patients’ sodium reduction efforts through dietary counseling. For example, counseling caregivers about the DASH diet, checking nutrition labels for sodium content, and choosing low-sodium foods like fruits and vegetables without added salt can help lower BP and reduce youths’ chronic disease risk.

References:

  1. Overwyk KJ, Zhao L, Zhang Z, Wiltz JL, Dunford EK, Cogswell ME. Trends in blood pressure and usual dietary sodium intake among children and adolescents, National Health and Nutrition Examination Survey 2003 to 2016. 2019;74(2):260-266. https://doi.org/10.1161/HYPERTENSIONAHA.118.12844.
  2. Flynn JT, Kaelber DC, Baker-Smith CM, et al; Subcommittee on Screening and Management of High Blood Pressure in Children. Clinical practice guideline for screening and management of high blood pressure in children and adolescents. Pediatrics. 2017;140(3): e20171904. https://doi.org/10.1542/peds.2017-1904.
  3. Falkner B, Daniels SR, Flynn JT, et al. The fourth report on the diagnosis, evaluation, and treatment of high blood pressure in children and adolescents. Pediatrics. 2004;114:555-576. https://www.nhlbi.nih.gov/sites/default/files/media/docs/hbp_ped.pdf.