[Forearm bone mineral density in healthy children]

In order to establish the normal patterns of forearm bone mineral density (BMD), BMD in the cortical and trabecular parts of the distal forearm were studied in a normal pediatric population.

BMD was measured by dual-energy X-ray absorptiometry (HOLOGIC QDR-1000) in the distal third forearm of 246 normal children and adolescents (111 boys and 135 girls) ranging from 2.8 to 20.8 years of age. BMD was correlated by multiple regression analysis with age, weight, body mass index (BMI), sex and pubertal Tanner stage.

Forearm BMD increased progressively with age, weight, height, BMI and maturity, with the maximal increase in all forearm bone sites occurring at the onset of puberty in girls and boys. A statistically significant correlation was found between forearm BMD and all of these variables (r = 0.65 to 0.92). Mean BMD was higher in boys than in girls in cortical, trabecular and cortical-trabecular sites of the distal forearm. Maximal differences in BMD between boys and girls occurred at 17-18 years of age, especially the trabecular-dominated (ultradistal) part of the distal forearm (0.446 vs 0.384 g/cm2).

Forearm BMD studies permit information of both cortical and trabecular bone mineralization to be obtained at the same time. This study reports normative data for forearm BMD in a healthy pediatric population. The values obtained may be used as a reference of normality when evaluating bone density in situations where skeletal mineralization may be compromised.