Determinants of skeletal age deviation in a cross-sectional study

Objective: Skeletal age deviation (SAD) is associated with bone mass and fracture risk in children, but factors determining this are unknown. The aim of this population-based cross-sectional study was to describe the factors associated with SAD. Methods: A convenience sample of 640 male and female children aged 7-17 yr was studied. All were assessed for body composition (dual-energy x-ray absorptiometry), diet, strength, dexterity, habitual physical activity, sunlight exposure, smoking, and medication use. Skeletal age was assigned using the Tanner-Whitehouse-2 method. Results: Subjects with a SAD greater than the 75th percentile had significantly higher height, weight, and Tanner stage compared with all other subjects. Bone-free lean mass, fat mass, and grip strength were positively associated with SAD. In multivariate analysis, ever smoking and use of inhaled corticosteroids were negatively associated with SAD, whereas milk drinking was positively associated with SAD. There was no significant association between sunlight exposure, television watching, light, or strenuous exercise and SAD. Conclusions: The results of this study should be regarded as hypothesis generating but are biologically plausible and suggest that body composition, strength, diet, ever smoking, and inhaled corticosteroid use may be determinants of bone maturity relative to age and thus affect fracture risk in children. However, more studies are necessary to explore other determinants of SAD such as genetic and perinatal factors and whether SAD influences peak bone mass. Copyright © 2008 by The Endocrine Society.