While establishing clear racial differences among children with hypertension, the study findings underscore the need for early diagnosis and prompt treatment of high blood pressure in all children, regardless of race and age. Indeed, more than half of the children in the study were either overweight or obese and more than one-third had heart-muscle abnormalities.

The study did not explore the reasons behind these racial differences, but the researchers hypothesize that they may be related to biological variations, diet, access to healthcare and low birth weight, which is more common in African-Americans and is a well-known risk factor for hypertension.

A single episode of high blood pressure is not necessarily hypertension, but investigators say that all children with one episode of high blood pressure during a visit to the doctor should be monitored. Clinically important hypertension is defined as elevated blood pressure on three consecutive visits. Normal blood pressure values for adults are 120/80 and under, but normal values in children vary by age, gender and height.

All children diagnosed with hypertension should be referred to a kidney specialist and have an ultrasound to check the heart muscle thickness and function.

More than 4 million children in the United States are estimated to have hypertension, a number that has increased five-fold over the last 30 years, likely because of growing obesity in children, among other factors, the researchers say.

SOURCE Johns Hopkins Children's Center