Accelerated skeletal maturity in children may point to primary hypertension

Advanced skeletal maturity may indicate primary hypertension in children, according to investigators from Poland.

“The main point of our study is that primary hypertension in children is strictly related [to] accelerated skeletal maturity,” Mieczyslaw Litwin, MD, PhD, a co-author of the study and scientific director of Children’s Memorial Health Institute in Warsaw, told ORTHOSuperSite.com. “It means that hypertensive children have more advanced biological maturity, and it is not explained by increased BMI. In other words, hypertensive children are biologically older than their normotensive, BMI-matched peers.”

The research appears in the October issue of Hypertension: Journal of the American Heart Association.

Litwin and her colleagues compared the X-rayed left hands of 54 Polish children and adolescents with hypertension to those of 54 healthy controls from the country who matched the study group for age, gender and BMI. Using images printed in a reference atlas of skeletal development, the investigators categorized the rate of maturity in both groups as physiological, accelerated and delayed.

The investigators noted that 20 children in the control group were skeletally mature compared to 48 children in the hypertension group, according to an American Heart Association press release.

They also found that the bone age and the chronological age were within a 4-month range and were not significantly different in the control group. However, they discovered a significant difference — nearly 2 years — between the average bone age and chronological age in the hypertension group.

Litwin cited the small study groups and inclusion of only Caucasian children as study limitations.

She said that it is difficult to identify any direct clinical implications of the research. However, it is known that biological maturity is linked to metabolic changes and sexual maturation.

Litwin noted that factors influencing body composition, including the relation between fat and lean body mass and the distribution of adipose tissue, may potentially impact the pace of biological maturity.

“It is known that physical activity not only increases lean body mass but may even cause clinically significant delay in biological maturity,” she said.

“Because about 20% of hypertensive children have metabolic syndrome, and because obesity is the main phenotype of hypertensive children, one may hypothesize that early, preventive lifestyle changes based on increased physical activity may impact not only body composition but also the pace of biological maturity. The problem of putative environmental factors (ie, dietary) causing accelerated skeletal maturity is still open,” Litwin added.

For more information:
Mieczyslaw Litwin, MD, PhD, can be reached at the department of nephrology & arterial hypertension, Children’s Memorial Health Institute, Al. Dzieci Polskich 20, 04-730 Warsaw, Poland; e-mail: m.litwin@czd.pl. The study was funded by the Children’s Memorial Health Institute in Warsaw.

References:
Pludowski P, Litwin M, Niemirska A, et al. Accelerated skeletal maturation in children with primary hypertension. Hypertension. Posted Oct 19, 2009 e-pub ahead of print.
www.americanheart.org