Much previous research has shown evidence linking childhood obesity to increased risk of hypertension (high blood pressure), particularly for children who are obese. U.S. data indicate that overweight children are 1.54 times as likely to have elevated blood pressure as children of average weight. For obese children, this prevalence ratio is 3.05 times.
However, the definition of what is normal weight for children is fairly broad. No information exists about the risks of hypertension for children whose body mass index (BMI) is on the high side of normal, but who are not defined as being overweight. Furthermore, there is no understanding of whether a child’s risk of hypertension changes if he or she gains extra weight (in addition to average expected increase) during childhood. A new study of over 800,000 youth between the ages of 3 and 17 has now addressed these gaps in knowledge.
The study looked retrospectively at the electronic health records of 801,019 young people who were members of Kaiser Permanente in Southern California between 2008 and 2015. The researchers considered the initial BMI and blood pressure of youths when they first joined the study, and monitored changes in these two variables during the 5-year follow-up period. They divided normal body weight into low (5th-39th percentiles), medium (40th-59th percentiles), and high (60th-84th percentiles) to provide insight into the risk of hypertension at a range of “normal” weights below the threshold for overweight.
The results of the analysis show that, in this cohort study of youths, high normal body weight (above the 60th percentile of BMI for age) was associated with increased risk of hypertension. In addition, extra weight gain was associated with further increases in hypertension risk. These findings are published in JAMA Network Open, and reveal the following:
“Hypertension during youth tracks into adulthood and is associated with cardiac and vascular organ damage. Since the organ damage can be irreversible, preventing hypertension in our young people is critically important,” said study lead author Dr. Corinna Koebnick of the Kaiser Permanente Southern California Department of Research & Evaluation. “The findings of this study of hypertension among a diverse population of children in Southern California show us the detrimental effects of even a few extra pounds on our young people.”
“This study underscores the need for medical professionals to re-evaluate how we correlate and educate about health risks across the spectrum of weight in growing children,” said study senior author Dr. Poornima Kunani, a pediatrician and researcher at the Kaiser Permanente Manhattan Beach Medical Office. “Obesity may be the most important risk factor for hypertension during childhood. Parents should talk to their pediatrician to see if their child might be at risk for hypertension and other preventable chronic medical conditions related to obesity. They can help you with strategies for developing habits to keep your child healthy through adulthood.”
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