title: Independent and combined effects of calcium-vitamin D3 and exercise on bone structure and strength in older men: an 18-month factorial design randomized controlled trial.
abstract: BACKGROUND
  Exercise and calcium-vitamin D are independently recognized as important strategies to prevent osteoporosis, but their combined effects on bone strength and its determinants remain uncertain.
  
  
  OBJECTIVE
  To assess whether calcium-vitamin D(3) fortified milk could enhance the effects of exercise on bone strength, structure, and mineral density in middle-aged and older men.
  
  
  METHODS
  An 18-month factorial design randomized controlled trial in which 180 men aged 50-79 years were randomized to the following: exercise + fortified milk; exercise; fortified milk; or controls. Exercise consisted of progressive resistance training with weight-bearing impact activities performed 3 d/week. Men assigned to fortified milk consumed 400 ml/d of 1% fat milk containing 1000 mg/d calcium and 800 IU/d vitamin D(3).
  
  
  METHODS
  Changes in bone mineral density (BMD), bone structure, and strength at the lumbar spine (LS), proximal femur, mid-femur, and mid-tibia measured by dual energy x-ray absorptiometry and/or quantitative computed tomography.
  
  
  RESULTS
  There were no exercise-by-fortified milk interactions at any skeletal site. Main effect analysis showed that exercise led to a 2.1% (95% confidence interval, 0.5-3.6) net gain in femoral neck section modulus, which was associated with an approximately 1.9% gain in areal BMD and cross-sectional area. Exercise also improved LS trabecular BMD [net gain 2.2% (95% confidence interval, 0.2-4.1)], but had no effect on mid-femur or mid-tibia BMD, structure, or strength. There were no main effects of the fortified milk at any skeletal site.
  
  
  CONCLUSIONS
  A community-based multi-component exercise program successfully improved LS and femoral neck BMD and strength in healthy older men, but providing additional calcium-vitamin D(3) to these replete men did not enhance the osteogenic response.
authors.affiliation: Department of Medicine, The University of Melbourne, Western Hospital, Footscray, Melbourne 3011, Australia. rdaly@unimelb.edu.au.
authors.forename: Sonja
authors.initials: S
authors.lastname: Kukuljan
authors.forename: Caryl A
authors.initials: CA
authors.lastname: Nowson
authors.forename: Kerrie M
authors.initials: KM
authors.lastname: Sanders
authors.forename: Geoff C
authors.initials: GC
authors.lastname: Nicholson
authors.forename: Markus J
authors.initials: MJ
authors.lastname: Seibel
authors.forename: Jo
authors.initials: J
authors.lastname: Salmon
authors.forename: Robin M
authors.initials: RM
authors.lastname: Daly
mesh_terms: D000368:Aged; D015519:Bone Density / Q000187:drug effects; D001842:Bone and Bones / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D002136:Calcium, Dietary / Q000008:administration & dosage / Q000494:pharmacology*; D002762:Cholecalciferol / Q000008:administration & dosage / Q000494:pharmacology*; D003131:Combined Modality Therapy; D019245:Compressive Strength / Q000187:drug effects; D004338:Drug Combinations; D004357:Drug Synergism; D015444:Exercise / Q000502:physiology*; D005081:Exercise Therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000503:physiopathology / Q000517:prevention & control*; D012107:Research Design; D013997:Time Factors
chemical_list: D002136:Calcium, Dietary; D004338:Drug Combinations; D002762:Cholecalciferol