Study highlights:

• Bones that grow ahead of chronological age may be an indicator of hypertension in children and adolescents.
• Researchers suggest that markers of biological maturity should be evaluated in hypertensive children.
• Physical activity and diet may deter the tempo of development of biological maturity.

DALLAS, Oct. 19, 2009 — 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 (the onset of signs of puberty before age 7 or 8 in girls and age 9 in boys),” 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.

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Statements and conclusions of study authors published in American Heart Association scientific journals are solely those of the study authors and do not necessarily reflect the association’s policy or position. The association makes no representation or guarantee as to their accuracy or reliability. The association receives funding primarily from individuals; foundations and corporations (including pharmaceutical, device manufacturers and other companies) also make donations and fund specific association programs and events. The association has strict policies to prevent these relationships from influencing the science content. Revenues from pharmaceutical and device corporations are available at www.americanheart.org/corporatefunding. 
 
NR09 – 1128 (Circ/Litwin)

Additional Resource: Visit the American Heart Association’s newly redesigned high blood pressure Web site – www.heart.org/hbp - to learn more about high blood pressure risk factors, treatment options, side effects and success rates.