title: Weight and body mass index predict bone mineral density and fractures in women aged 40 to 59 years.
abstract: Weight and body mass index are associated with low bone mineral density and fractures in older women. This retrospective cohort study confirms a similar relationship in women aged 40 to 59 years.
  
  
  BACKGROUND
  Risk factors for the prediction of osteoporosis and fractures have been less thoroughly studied in younger women. We evaluated the associations between weight, body mass index (BMI), the Osteoporosis Self-Assessment Tool (OST), bone mineral density (BMD) and fracture risk in women aged 40 to 59 years.
  
  
  METHODS
  Using administrative health management databases, we conducted a retrospective cohort study in 8,254 women aged 40-59 years who had baseline BMD testing. Linear regression and Cox proportional multivariate models were created to examine the associations with weight, BMI, OST, BMD, and subsequent fractures throughout a 3.3-year follow-up.
  
  
  RESULTS
  Body weight, BMI, and OST had a similar overall performance in their ability to classify women with femoral neck T-score < or = -2.5. Throughout 27,256 person years of observation, 225 women experienced one or more fractures. After adjustment for age, prevalent fractures, and use of corticosteroids, each standard deviation decrease in weight was associated with a 19% increase in the risk of incident fracture (95% CI: 1.01-1.35). Femoral neck BMD and the presence of prevalent fractures were also associated with the risk of incident fractures.
  
  
  CONCLUSIONS
  Low weight and BMI predict osteoporosis and are associated with increased fracture risk in younger women. The negative impact of low body weight on bone health should be more widely recognized.
authors.affiliation: Department of Medicine, McGill University, Montreal, Canada. suzanne.morin@mcgill.ca
authors.forename: S
authors.initials: S
authors.lastname: Morin
authors.forename: J F
authors.initials: JF
authors.lastname: Tsang
authors.forename: W D
authors.initials: WD
authors.lastname: Leslie
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D015992:Body Mass Index; D001835:Body Weight / Q000502:physiology*; D015519:Bone Density / Q000502:physiology*; D015331:Cohort Studies; D005260:Female; D005272:Femur Neck / Q000000981:diagnostic imaging / Q000503:physiopathology; D050723:Fractures, Bone / Q000000981:diagnostic imaging / Q000453:epidemiology*; D006801:Humans; D008350:Manitoba / Q000453:epidemiology; D008875:Middle Aged; D010024:Osteoporosis / Q000000981:diagnostic imaging / Q000453:epidemiology*; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D012680:Sensitivity and Specificity