Bone Mineral Density in Children and Adolescents: Relation to Puberty, Calcium Intake, and Physical Activity¹

TLDR

The study assessed the relationship between height, weight, pubertal stage, calcium intake, and physical activity and bone mineral density in 500 children and adolescents using dual‑energy X‑ray absorptiometry of the lumbar spine and total body, with volumetric BMD calculated to correct for bone size. Bone mineral density and volumetric BMD increased with age, with pubertal stage the strongest independent predictor in girls and body weight the strongest predictor in boys, while calcium intake and physical activity were positively associated with BMD only in boys.

Abstract

The association of height, weight, pubertal stage, calcium intake, and physical activity with bone mineral density (BMD) was evaluated in 500 children and adolescents (205 boys and 295 girls), aged 4–20 yr. The BMD (grams per cm2) of lumbar spine and total body was measured with dual energy x-ray absorptiometry. Lumbar spine volumetric BMD was calculated to correct for bone size. BMD and volumetric BMD increased with age. During puberty, the age-dependent increment was higher. After adjustment for age, the Tanner stage was significantly associated with all three BMD variables in girls and with spinal BMD in boys. In boys, positive correlations were found between BMD and both calcium intake and physical activity after adjustment for age. Stepwise regression analysis with weight, height, Tanner stage, calcium intake, and physical activity as determinants with adjustment for age resulted in a model with Tanner stage in girls and weight in boys for all three BMD variables. The major independent determinant of BMD was the Tanner stage in girls and weight in boys.