Regional and total body bone mineral content, bone mineral density, and total body tissue composition in children 8?16 years of age

Abstract

Normative values for total body bone mineral content (TBBM) and total body bone mineral density (TBMD) were derived from measurements on 234 children 8-16 years of age. In addition, bone mineral content (BMC) and bone mineral density (BMD) values for selected regions of interest and soft tissue (bone free lean and fat) for the total body are presented. Bone mineral and soft tissue values were determined by dual energy X-ray absorptiometry (DXA) using a Hologic QDR-2000 in the array mode. Results of a stepwise multiple regression analysis revealed a significant correlation between bone-free lean tissue (BFLT) and BMD (r2 = 0.80) in girls. Adding age to the equation accounted for an additional 2% of the variance (P < 0.05) and height accounted for another 1% of the variance (P < 0.05). Body weight and fat tissue (FT) did not account for any additional variance. In boys BFLT correlated significantly with BMD (r2 = 0.75; P < 0.05); none of the other predictor variables accounted for additional variance. No significant differences were found in TBBM or TBMD between boys and girls at any age. There was a significant overall gender effect for only three regions of interest. Boys had greater BMC in the head region and had greater BMD in the upper limbs, but post hoc analysis revealed no significant differences for any specific age groups. Girls had greater overall BMD in the pelvis, but this difference was only significant at the 15-16-year age group. The changes in BFLT and FT over the age ranges were consistent with the growth literature.(ABSTRACT TRUNCATED AT 250 WORDS)

Longitudinal Bone Mineral Density Changes in Female Child Artistic Gymnasts

“…(35) While controls in the current study had a lower percentage increase in FN BMD (3.9 ± 1.6%) but a higher percentage increase in LS BMD (6.8 ± 1.6%) than published norms, (35) gymnasts had an even higher gain at both sites (6.1 ± 1.2% and 7.8 ± 1.1%, respectively) than controls and other young females. Faulkner et al (36) reported a 3.7% difference in TB BMD between 10-and 11-year-old females. Although this was a cross-sectional comparison, (36) it is similar to our longitudinal findings (3.4 ± 0.7% gain/year) in controls.…”

“…Faulkner et al (36) reported a 3.7% difference in TB BMD between 10-and 11-year-old females. Although this was a cross-sectional comparison, (36) it is similar to our longitudinal findings (3.4 ± 0.7% gain/year) in controls. Thus, the available literature also supports the idea that there is an approximate 2.0% annual gain in gymnasts above that observed in less active females.…”

“…(39)(40)(41) Specifically it has been suggested that in girls, 80% of the variability in BMD is explained by FFST mass. (36) Although genetic predisposition for high FFST mass and low FM in gymnasts cannot be discounted, the highly muscular body type appears beneficial to BMD. In fact, a recent study by Morris et al (42) showed that changes in FFST mass accounted for 10-58% of the variability in BMD accrual in 9-to 10-year-old premenarcheal girls who completed a 10-month exercise intervention program.…”

Changes and Tracking of Fat Mass in Pubertal Girls

“…From these studies we can conclude that the distribution and development of fat mass is different in boys and girls (1)(2)(3)(4)(5)(6). The current obesity epidemic urges us to learn more about the physiologic development of fat mass during puberty, a critical period in body composition development.…”

“…The present knowledge is mainly based on cross-sectional research using methods like BMI and skinfold measurements. This current study uses dual-energy X-ray absorptiometry (DXA) to measure body composition, which has been proven to be an accurate, valid, and reproducible measure for body composition (3,8,9).…”