title: Bone mineral density in healthy female adolescents according to age, bone age and pubertal breast stage.
abstract: OBJECTIVE
  This study was designed to evaluate bone mineral density (BMD) in healthy female Brazilian adolescents in five groups looking at chronological age, bone age, and pubertal breast stage, and determining BMD behavior for each classification.
  
  
  METHODS
  Seventy-two healthy female adolescents aged between 10 to 20 incomplete years were divided into five groups and evaluated for calcium intake, weight, height, body mass index (BMI), pubertal breast stage, bone age, and BMD. Bone mass was measured by bone densitometry (DXA) in lumbar spine and proximal femur regions, and the total body. BMI was estimated by Quetelet index. Breast development was assessed by Tanner's criteria and skeletal maturity by bone age. BMD comparison according to chronologic and bone age, and breast development were analyzed by Anova, with Scheffe's test used to find significant differences between groups at P≤0.05.
  
  
  RESULTS
  BMD (g·cm(-2)) increased in all studied regions as age advanced, indicating differences from the ages of 13 to 14 years. This group differed to the 10 and 11 to 12 years old groups for lumbar spine BMD (0.865±0.127 vs 0.672±0.082 and 0.689±0.083, respectively) and in girls at pubertal development stage B3, lumbar spine BMD differed from B5 (0.709±0.073 vs 0.936±0.130) and whole body BMD differed from B4 and B5 (0.867±0.056 vs 0.977±0.086 and 1.040±0.080, respectively).
  
  
  CONCLUSIONS
  Bone mineralization increased in the B3 breast maturity group, and the critical years for bone mass acquisition were between 13 and 14 years of age for all sites evaluated by densitometry.
authors.affiliation: Clinical and Experimental Pediatrics Research Centre, Department of Pediatrics, Botucatu School of Medicine - UNESP, São Paulo State University, Brazil.
authors.forename: Maria Regina
authors.initials: MR
authors.lastname: Moretto de Oliveria
authors.forename: Carla
authors.initials: C
authors.lastname: Cristiane da Silva
authors.forename: Cilmery Suemi
authors.initials: CS
authors.lastname: Kurokawa
authors.forename: Cristina Maria
authors.initials: CM
authors.lastname: Teixeira Fortes
authors.forename: Renata
authors.initials: R
authors.lastname: Campos Capela
authors.forename: Altamir
authors.initials: A
authors.lastname: Santos Teixeira
authors.forename: José
authors.initials: J
authors.lastname: Carlos Dalmas
authors.forename: Tamara Beres
authors.initials: TB
authors.lastname: Lederer Goldberg