Bones that are more mature than their chronological age may be a marker for high blood pressure in children, according to a study published in Hypertension: Journal of the American Heart Association.

Skeletal maturation, or bone age, refers to changes in the size and shape of bones that can be used to predict adult height and structural development.

In non-hypertensive children, bone age was not significantly different from chronological age - within a four-month range. But in hypertensive children, the difference between average chronological age (14.15 years) and bone age (16.01 years) was nearly two years.

"Accelerated maturation is not the same as precocious puberty," said Mieczyslaw Litwin, M.D., Ph.D., co-author of the study and scientific director of Children's Memorial Health Institute in Warsaw, Poland. "Accelerated maturation means that the tempo of biological maturity is greater than average. We found that accelerated skeletal maturation may be the early tell-tale sign of developing hypertension."

To examine the relationship between blood pressure and skeletal maturation, researchers assessed bone age in hypertensive children and adolescents compared with healthy young people matched for body mass index, age and gender.

Researchers X-rayed the left hand-wrists of 54 hypertensive white Polish children and compared them to X-ray images of 54 white Polish children with optimal blood pressure. Both groups were compared with images published in a reference atlas of skeletal development. The children were age 14 on average. Based on the atlas, rates of maturity were considered physiological, accelerated and delayed.

In healthy controls, researchers found skeletal maturity in 20 cases compared with 48 cases among the hypertensive group.

Researchers also studied the relationship between hypertension and bone age to obesity.

The results were significant, but no direct clinical application was found. However, researchers said accelerated bone maturation is only a sign of hormonal and metabolic abnormalities.

"It is difficult to imagine that the process of biological maturity can be reversed," said Litwin, who also is an associate professor in the Department of Nephrology & Arterial Hypertension at the institute. "But, we think that some lifestyle modifications, such as increased physical activity and diet modification, can influence both metabolic abnormalities and the tempo of biological maturity."

Other co-authors are: Pawel Pludowski, Ph.D.; Anna Niemirska, M.D.; Joanna Sladowska, M.D.; Roman Lorenc, M.D., Ph.D.; Maciej Jaworski, Ph.D.; Edyta Kryskiewicz, M.Sc. and Elzbieta Karczmarewicz, Ph.D.

The Children's Memorial Health Institute in Warsaw, Poland funded the study.