title: Preferred skeletal site for osteoporosis screening in high-risk populations.
abstract: OBJECTIVE
  The current World Health Organization (WHO) definition of osteoporosis, which is based on densitometry of lumbar and femoral regions, is extensively used for decision-making in clinical practice. Discordance in diagnosis of osteoporosis using this definition is a known phenomenon. The aim of this study was to evaluate the impact of such discordance and to assess the diagnostic value of using one skeletal site for screening purposes as opposed to the two sites required in the WHO criteria.
  
  
  METHODS
  Data was collected from 4188 individuals (3848 female); mean age=53.4 years (standard deviation 11.8) referred to a community-based outpatient osteoporosis testing centre in Tehran, Iran.
  
  
  METHODS
  Dual-energy X-ray absorptiometry (DXA) was performed on L1-L4 lumbar spine and total hip for all cases. The DXA results were categorized according to WHO criteria. Sensitivity for each site was calculated as number of cases with T-score < -2.5 at that site divided by the total number of cases with T-score < -2.5 at any site.
  
  
  RESULTS
  Prevalence of osteoporosis diagnosis using lumbar DXA, femoral DXA, and WHO criteria (either of the sites) were 24.7%, 12.4%, and 27.8%, respectively. Sensitivity of lumbar DXA for diagnosis of osteoporosis (88.9%) was significantly higher than femoral DXA (44.6%, P<0.001); but this difference became non-significant for men > or = 60 and women > or = 70 (P=0.615 and P=0.077, respectively). Agreement of the procedures in different sites (kappa) was 0.40 (0.37 to 0.43). When proximal femur was considered as the reference, positive likelihood ratios of lumbar DXA to detect cases were 4.7 and 2.0 in younger and older groups, respectively.
  
  
  CONCLUSIONS
  Concerning the high rate of discordance and low agreement between DXA results, the data obtained from each anatomical site cannot predict the condition of the other site. However, if use of a single assessment is intended for screening programs, public health authorities can develop different strategies for different age groups of their population. We propose lumbar DXA for the younger group (men < 60 and women < 70) and femoral densitometry for the older.
authors.affiliation: Endocrinology and Metabolism Research Centre, Shariati Hospital, Tehran University of Medical Sciences, North Kargar Ave, Tehran 14114, Iran. moayyeri@doctor.com
authors.forename: Alireza
authors.initials: A
authors.lastname: Moayyeri
authors.forename: Akbar
authors.initials: A
authors.lastname: Soltani
authors.forename: Hossein
authors.initials: H
authors.lastname: Bahrami
authors.forename: Mohsen
authors.initials: M
authors.lastname: Sadatsafavi
authors.forename: Mehdi
authors.initials: M
authors.lastname: Jalili
authors.forename: Bagher
authors.initials: B
authors.lastname: Larijani
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods*; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging; D006615:Hip / Q000000981:diagnostic imaging; D006801:Humans; D007492:Iran / Q000453:epidemiology; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging; D008297:Male; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D010024:Osteoporosis / Q000175:diagnosis* / Q000453:epidemiology; D012307:Risk Factors; D012680:Sensitivity and Specificity; D014944:World Health Organization