title: Physical activity is the strongest predictor of calcaneal peak bone mass in young Swedish men.
abstract: CONCLUSIONS
  In a highly representative sample of young adult Swedish men (n = 2,384), we demonstrate that physical activity during childhood and adolescence was the strongest predictor of calcaneal bone mineral density (BMD), and that peak bone mass was reached at this site at the age of 18 years.
  
  
  BACKGROUND
  The purpose of the present study was to determine if physical activity during growth is associated with peak calcaneal BMD in a large, highly representative cohort of young Swedish men.
  
  
  METHODS
  In this study, 2,384 men, 18.3 +/- 0.3 (mean +/- SD) years old, were included from a population attending the mandatory tests for selection to compulsory military service in Sweden. BMD (g/cm(2)) of the calcaneus was measured using dual-energy X-ray absorptiometry. Training habits were investigated using a standardized questionnaire.
  
  
  RESULTS
  Regression analysis (with age, height, weight, smoking, and calcium intake as covariates) demonstrated that history of regular physical activity was the strongest predictor and could explain 10.1% of the variation in BMD (standardized beta = 0.31, p < 0.001). A regression model with quadratic age effect revealed maximum BMD at 18.4 years.
  
  
  CONCLUSIONS
  We found that history of physical activity during growth was the strongest predictor of peak calcaneal BMD in young men.
authors.affiliation: Sport Medicine Unit, Department of Surgical and Perioperative Sciences, Umeå University, Umeå, Sweden.
authors.forename: U
authors.initials: U
authors.lastname: Pettersson
authors.forename: M
authors.initials: M
authors.lastname: Nilsson
authors.forename: V
authors.initials: V
authors.lastname: Sundh
authors.forename: D
authors.initials: D
authors.lastname: Mellström
authors.forename: M
authors.initials: M
authors.lastname: Lorentzon
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods; D000293:Adolescent; D000375:Aging / Q000502:physiology; D015519:Bone Density / Q000502:physiology*; D002111:Calcaneus / Q000254:growth & development / Q000502:physiology*; D015331:Cohort Studies; D006801:Humans; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D053580:Muscle Strength / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology; D013548:Sweden; D055815:Young Adult