title: Regional differences in hip bone mineral density levels in Norway: the NOREPOS study.
abstract: CONCLUSIONS
  Large regional differences in hip fracture rates within Norway have previously been shown. However, regional differences in hip bone mineral density (BMD) have not yet been assessed. In this study including 10,504 hip scans, there were significant regional differences in BMD. Further studies to address reasons for the regional differences in hip fracture risk are warranted.
  
  
  BACKGROUND
  Bone mineral density (BMD) at the hip is an important determinant of hip fracture. While regional differences in Norwegian hip fracture rates have previously been shown, no comparative studies of hip BMD have been conducted.
  
  
  METHODS
  Total hip BMD was measured by DXA in two population-based studies across Norway during 1997-2002. Valid hip scans with in vivo calibration were obtained from 5127 subjects in Tromsø (age 30-89 years) and 5377 subjects in Bergen (age 47-50 and 71-75 years).
  
  
  RESULTS
  Women >or=60 years in Tromsø had 0.052 g/cm(2) higher age-adjusted BMD than women in Bergen, whereas BMD among women <60 years was similar in Tromsø and Bergen. Age-adjusted total hip BMD was 0.035 g/cm(2) lower in men >or=60 years in Bergen compared with Tromsø, and the corresponding figure for men <60 years was 0.028 g/cm(2). While adjustment for body mass index explained some, but not all of the differences, smoking, physical activity, diabetes prevalence, self-perceived health, intake of alcohol and estrogen use did not.
  
  
  CONCLUSIONS
  Regional differences in BMD at the hip were found in Norway. Reasons for this and potential impact on hip fracture rates should be explored in further studies.
authors.affiliation: Section for Preventive Medicine and Epidemiology, Institute of General Practice and Community Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway. t.k.omsland@medisin.uio.no
authors.forename: T K
authors.initials: TK
authors.lastname: Omsland
authors.forename: C G
authors.initials: CG
authors.lastname: Gjesdal
authors.forename: N
authors.initials: N
authors.lastname: Emaus
authors.forename: G S
authors.initials: GS
authors.lastname: Tell
authors.forename: H E
authors.initials: HE
authors.lastname: Meyer
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology; D015519:Bone Density / Q000502:physiology*; D001851:Bone Diseases, Metabolic / Q000453:epidemiology / Q000503:physiopathology; D005260:Female; D006306:Health Surveys; D006621:Hip Joint / Q000502:physiology* / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009664:Norway / Q000453:epidemiology; D010024:Osteoporosis / Q000453:epidemiology* / Q000503:physiopathology; D015663:Osteoporosis, Postmenopausal / Q000453:epidemiology / Q000503:physiopathology; D017678:Sex Distribution