DALLAS - Adolescent boys are far more likely to suffer high blood pressure than girls in the same age group, setting the stage for other health problems such as hypertension as they get older, researchers reported on Monday.

"The reason remains a mystery but it could be hormonal. We think it may have something to do with the onset of puberty in boys," said Dr. Kaberi Dasgupta, lead author of the study and a physician at McGill University Health Center in Montreal.

Men are usually more prone to hypertension - chronically elevated blood pressure that can lead to heart disease - than women. But this is the first study to highlight gender differences in blood pressure among adolescents.

Researchers hope it could lead to more effective measures to prevent hypertension among young adult males.

The five-year study looked at 614 boys and 653 girls in Montreal secondary schools.

Over the course of the study it found that the risk of systolic blood pressure (SBP) - the larger of the two numbers that comprise a blood pressure reading - increased annually by 19 percent for boys but remained stable for girls.

It also pointed to a lack of exercise and a sedentary lifestyle as increasing the risk of higher SBP for both boys and girls.

"Even after adjusting for differences in body weight, the more frequently a child engaged in active behavior, the lower the likelihood of developing higher systolic blood pressure levels," Dasgupta said.

"The more hours that the kids spent in sedentary behaviors - sitting at a computer, playing video games, being on the Internet, watching television - the more risk of having higher systolic blood pressure," she added.

The results of the study are published this week in Circulation: Journal of the American Heart Association.

The researchers are members of GENESIS, a Canadian group that explores gender differences in cardiovascular disease.