(CNN) -- The number of hospitalizations for children with high blood pressure more than doubled from 1997 to 2006, according to a new study. The number rose from 12,661 hospitalizations in 1997 to 24,602 in 2006. The study is published in the American Heart Association journal, Hypertension.
"There have been some published studies that have demonstrated an increase in frequency of hypertension among kids in the outpatient settings in the clinics," said Dr. Cheryl Tran, study author and fellow in the Department of Pediatric Nephrology at the University of Michigan.
"In our study, we found we also are seeing this trend in the inpatient setting," she said.
"It definitely was surprising- we may be seeing a reflection of that from the rise in hypertension from the outpatient setting, but I think what was also alarming was the economic burden created by the inpatient pediatric hypertension."
The cost of the hospitalizations in the 10 years reviewed reached an estimated $3.1 billion, according to the study.
The researchers reviewed hospital discharge data for the study. They included all children aged 2 to 18 who were treated for hypertension during hospitalizations, regardless of their primary diagnosis or the main reason why they were hospitalized.
Those most likely to have high blood pressure were older than 9, male and African-American, according to the study. Some had end-stage renal (kidney) disease.
The study found children with hypertension had an average length of stay of eight days- double that of non-hypertensive kids.
Childhood obesity may play a role in the sharp increase in hospitalizations.
American Heart Association spokesman Dr. Ernesto Schiffrin from the Department of Medicine at McGill University, Montreal, Quebec said obesity seems to be an even stronger risk factor for high blood pressure in children than it is in adults.
"Increasingly, these are children with essential hypertension- this is consequence of the epidemic of obesity and diabetes that is found increasingly in teenagers and younger children," he said.
"If we are going to prevent adult hypertension, we have to start at this early age by avoiding obesity, cutting back on salt and exercising- otherwise this will increase further the prevalence of adult hypertension and the huge costs that will occur accordingly."
Both parents and children need to be educated about healthy eating, cutting back on calories and increasing exercise, Schiffrin added.