Previously, systolic blood pressures of 100, 105 and 110 were considered within the normal range for adolescents. However, the study found that elevations in blood pressure within the normal range can be consistent with pre-hypertension and represent higher risk of developing hypertension later in life.
Researchers examined the development of blood pressure from adolescence to young adulthood in 23,191 boys and 3,789 girls from average age 17 to 42 years, with regular and repeated readings of blood pressure and body mass index (BMI). Participants were part of the Metabolic, Lifestyle, and Nutrition Assessment in Young Adults (MELANY) Study, conducted by the Israeli Defense Forces.
“Blood pressure values well below the hypertensive range can serve as good predictors for future hypertension,” said Amir Tirosh, MD, PhD, lead study authors and a fellow in the Department of Medicine, Division of Endocrinology, Diabetes, and Hypertension at BWH. “The rate of progression to hypertension is higher in teen-agers whose systolic blood pressure is 110 versus those whose blood pressure is 100.”
Researchers also examined the interaction between BMI and blood pressure, because of concerns about the current obesity epidemic. Teens that are overweight or obese are already at a 25 percent higher risk of developing hypertension compared to those of lower weight. For boys, the risk of high blood pressure as adults increases throughout the entire range of BMI. For girls, only the sub-group considered obese had substantially higher risk of high blood pressure.
“BMI is considered an independent risk factor that interacts with blood pressure to predict future risk of hypertension,” Tirosh said. “Together, these factors provide a simple and useful tool that can serve as a red flag to detect sub-groups of teens at high risk of hypertension as adults while in their teens.”
“It is never too early to start lifestyle modification and intervene to prevent hypertension, heart disease and diabetes,” he said. “Hypertension has been perceived as more relevant to an older population, but now we know that slight changes in blood pressure and weight represent an alert for prevention. We know that preventing the disease is much easier than treating it.”
The study was funded by the Talpiot Medical Leadership Program, Chaim Sheba Medical Center, Tel-Hashomer, Israel and the Israeli Defense Forces Medical Corps.