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The Relationship Between Greater Prepubertal Adiposity, Subsequent Age of Maturation, and Bone Strength During Adolescence
Author(s) -
Glass Natalie A,
Torner James C,
Letuchy Elena M,
Burns Trudy L,
Janz Kathleen F,
Eichenberger Gilmore Julie M,
Schlechte Janet A,
Levy Steven M
Publication year - 2016
Publication title -
journal of bone and mineral research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.882
H-Index - 241
eISSN - 1523-4681
pISSN - 0884-0431
DOI - 10.1002/jbmr.2809
Subject(s) - medicine , femoral neck , percentile , body mass index , bone age , lean body mass , overweight , bone mineral , peak bone mass , endocrinology , osteoporosis , body weight , mathematics , statistics
This longitudinal study investigated whether greater prepubertal adiposity was associated with subsequent timing of maturation and bone strength during adolescence in 135 girls and 123 boys participating in the Iowa Bone Development Study. Greater adiposity was defined using body mass index (BMI) data at age 8 years to classify participants as overweight (OW, ≥85th percentile for age and sex) or healthy weight (HW). Maturation was defined as the estimated age of peak height velocity (PHV) based on a series of cross‐sectional estimates. Measurements were taken at ages 11, 13, 15, and 17 years for estimates of body composition by dual‐energy X‐ray absorptiometry (DXA), bone compression (bone strength index), and torsion strength (polar strength‐strain index) at the radius and tibia by pQCT, and femoral neck bending strength (section modulus) by hip structural analysis. Bone strength in OW versus HW were evaluated by fitting sex‐specific linear mixed models that included centered age (visit age – grand mean age of cohort) as the time variable and adjusted for change in fat mass, and limb length in model 1. Analyses were repeated using biological age (visit age – age PHV) as the time variable for model 1 with additional adjustment for lean mass in model 2. BMI was negatively associated with age of maturation ( p < 0.05). OW versus HW girls had significantly greater bone strength ( p < 0.001) in model 1, whereas OW versus HW boys had significantly greater bone strength ( p < 0.001) at the tibia and femoral neck but not radius ( p > 0.05). Analyses were repeated using biological age, which yielded reduced parameter estimates for girls but similar results for boys (model 1.) Differences were no longer present after adjustment for lean mass (model 2) in girls ( p > 0.05) whereas differences at the tibia were sustained in boys ( p < 0.05). These findings demonstrate sex‐ and site‐specific differences in the associations between adiposity, maturation, and bone strength. © 2016 American Society for Bone and Mineral Research.