Pubertal Changes in Bone Mineral Content of The Wrist and Spine in Normal Boys and Girls

Abstract

We measured the bone mineral content of the wrist and spine using single and dual photon absorptiometry (SPA and DPA) in 165 normal boys and girls to quantitate the contribution of normal pubertal development to the attainment of adult bone mass. We constructed bone density ranges for spine and wrist bone density for each pubertal stage in girls (breast) and boys (pubic hair). Wrist bone density measurements (±SD) for girls and boys, pubertal stages 1 and 5, were 0.41±0.06 and 0.62±0.05gm/cm2 (girls) and 0.46±0.08 and 0.70±0.08gm/cm2 (boys), respectively. Spine bone density measurements (±SD) for girls and boys, pubertal stages 1 and 5, were 0.78±0.09 and 1.18±0.13gm/cm2 (girls) and 0.81±0.10 and 1.22±0.23gm/cm2 (boys), respectively. Thus, bone mineral content of the wrist and spine increased during pubertal development (between stage 1 and 5) by approximately 50% for boys and girls. The wrist bone density of boys was significantly greater than that of girls (p<0.03). Bone mineral content of the spine was similar for boys and girls throughout pubertal development. The bone mineral content of the wrist and spine in girls and boys correlated significantly with chronologic age, bone age, body mass index, height age, height, weight, serum IGF-I, and testosterone (boys), (all p<0.0001). We conclude that bone density of the wrist but not the spine is increased in boys versus girls, that bone mineral content increases by approximately 50% between Tanner stage 1 and 5 for both sexes, and that bone mineral content at both sites correlates with advances in pubertal development.