A new study from Kaiser Permanente found an increased body mass during youth was associated with a 26% greater risk of developing hypertension later in life.

An analysis of electronic medical record data from more than 800,000 people between the age of 3-17 years, results of the study indicate each single BMI unit gained per year increased the risk of hypertension by 4%, with those at the high end of the average weight range at a 26% greater risk than their counterparts in the medium range of average weight.¹

“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 lead investigator Corinna Koebnick, PhD, of the Kaiser Permanente Southern California Department of Research & Evaluation.² “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.”

As obesity rates continue to balloon among adults in the US and abroad, the impact of associated cardiometabolic risk has been thrust into the spotlight, with contemporary data creating further concern related to the impact of the pandemic on rates of obesity and overweight in younger populations. A recent study of more than 25,000 children in Sweden found the proportion of 3- and 4-year-olds with overweight increased from 9.5% to 12.4% during the COVID-19 pandemic and rates of obesity among these children increased from 2.5% to 4.4%.³

For the current study, Koebnick and colleagues from within the Kaiser Permanente Health System sought to explore how increased BMI for age and weight trajectories in youth might influence the risk of hypertension later in life. With this in mind, investigators designed a retrospective analysis leveraging electronic medical record data from an integrated health system in California. From this data, investigators obtained information from a cohort of 801,019 youths aged 3-17 years with a baseline visit from January 1, 2008-February 28, 2015, with a maximum follow-up of 5 years from January 1, 2008-February 28, 2020.¹

The primary outcome of interest was risk of hypertension based on first available sex-specific BMI for age and change in the distance to the median BMI for age during the 5-year follow-up, with adjustment for sex, race and ethnicity, socioeconomic status, baseline year, and birth year. Investigators pointed out Cox proportional hazards regression models with age as a time scale was used to assess hypertension risk.¹

The cohort of 801,019 youths identified for inclusion in the analyses had a mean age of 9.4 (SD, 4.6) years and 51.1% were female. This cohort had a total follow-up of 3,579,994 person-years of follow-up, with a mean follow-up time of 4.47 (SD, 1.20) years and mean number of office visits with blood pressure measurement of 9.9 (SD, 7.4). When examining race and ethnicity, 7.4% were Asian and Pacific Islanders, 8.2% were Black, and 53.4% were Hispanic.¹

When compared to youths with a baseline BMI for age in the 40th-59th percentiles, those in the 60th-84th percentiles had a 26% greater risk of hypertension in adjusted analyses (aHR, 1.26 [95% CI, 1.20-1.33]). Further analysis indicated every 1-unit annual increase in the distance to the median BMI for age was associated with a 4% increase in relative risk (aHR, 1.04 [95% CI, 1.04-1.05]). Investigators pointed out those with a baseline BMI for age in the 97th percentile or higher who maintained their body weight had a nearly 5-fold increase in risk of hypertension compared to their counterparts with a BMI in the 40th-59th percentiles (aHR, 4.94 [95% CI, 4.72-5.18]).¹

“This study underscores the need for medical professionals to reevaluate how we correlate and educate about health risks across the spectrum of weight in growing children,” said senior investigator Poornima Kunani, MD, a pediatrician and researcher at the Kaiser Permanente Manhattan Beach Medical Office.² “Obesity may be the most important risk factor for hypertension during childhood. Parents should talk to their pediatrician to see if your 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.”