title: Bone loss and fracture risk after reduced physical activity.
abstract: Former male young athletes partially lost benefits in BMD (g/cm2) with cessation of exercise, but, despite this, had a higher BMD 4 years after cessation of career than a control group. A higher BMD might contribute to the lower incidence of fragility fractures found in former older athletes > or =60 years of age compared with a control group.
  
  
  BACKGROUND
  Physical activity increases peak bone mass and may prevent osteoporosis if a residual high BMD is retained into old age.
  
  
  METHODS
  BMD was measured by DXA in 97 male young athletes 21.0 +/- 4.5 years of age (SD) and 48 controls 22.4 +/- 6.3 years of age, with measurements repeated 5 years later, when 55 of the athletes had retired from sports. In a second, older cohort, fracture incidence was recorded in 400 former older athletes and 800 controls > or =60 years of age.
  
  
  RESULTS
  At baseline, the young athletes had higher BMD than controls in total body (mean difference, 0.08 g/cm2), spine (mean difference, 0.10 g/cm2), femoral neck (mean difference, 0.13 g/cm2), and arms (mean difference, 0.05 g/cm2; all p < 0.001). During the follow-up period, the young athletes who retired lost more BMD than the still active athletes at the femoral neck (mean difference, 0.07 g/cm2; p = 0.001) and gained less BMD at the total body (mean difference, 0.03 g/cm2; p = 0.004). Nevertheless, BMD was still higher in the retired young athletes (mean difference, 0.06-0.08 g/cm2) than in the controls in the total body, femoral neck, and arms (all p < 0.05). In the older cohort, there were fewer former athletes > or =60 of age than controls with fragility fractures (2.0% versus 4.2%; p < 0.05) and distal radius fractures (0.75% versus 2.5%; p < 0.05).
  
  
  CONCLUSIONS
  Although exercise-induced BMD benefits are reduced after retirement from sports, former male older athletes have fewer fractures than matched controls.
authors.affiliation: Department of Public Health and Clinical Medicine, University of Umeö, Umeö, Sweden. anna.nordstrom@idrott.umu.se
authors.forename: Anna
authors.initials: A
authors.lastname: Nordström
authors.forename: Caroline
authors.initials: C
authors.lastname: Karlsson
authors.forename: Fredrik
authors.initials: F
authors.lastname: Nyquist
authors.forename: Tommy
authors.initials: T
authors.lastname: Olsson
authors.forename: Peter
authors.initials: P
authors.lastname: Nordström
authors.forename: Magnus
authors.initials: M
authors.lastname: Karlsson
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D000367:Age Factors; D000368:Aged; D000704:Analysis of Variance; D015519:Bone Density; D016022:Case-Control Studies; D015331:Cohort Studies; D015444:Exercise; D050723:Fractures, Bone / Q000175:diagnosis* / Q000453:epidemiology*; D006688:Hockey; D006801:Humans; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000517:prevention & control; D012306:Risk; D012916:Soccer; D013177:Sports; D013997:Time Factors