title: Knee osteoarthritis is associated with increased prevalence of vertebral fractures despite high systemic bone mineral density: a cross-sectional study in an Asian population.
abstract: OBJECTIVE
  This study aimed to evaluate the relationship between radiographic knee osteoarthritis and vertebral fractures (VFs) in an Asian population.
  
  
  METHODS
  This cross-sectional study involved data from 1,829 participants of the Fifth Korean National Health and Nutrition Examination Survey. Radiographic knee osteoarthritis was defined as Kellgren-Lawrence (KL) grades ≥ 2. Prevalent VF was defined as a loss of ≥ 4 cm of height from the peak height. BMD was measured using dual-energy X-ray absorptiometry, in the lumbar spine and femoral neck.
  
  
  RESULTS
  In both sexes, the prevalence of VFs increased with age, and was higher in the knee osteoarthritis group than in the control group (in men 13.2 % in osteoarthritis group and 7.9 % in control group; in women 27.7 % in osteoarthritis group and 14.7 % in control group). Age-adjusted BMD at the lumbar spine and femoral neck was significantly higher in the knee osteoarthritis group. In multivariable analysis, KL grade 4 was significantly associated with vertebral fractures in men. In women, there was a significant trend for a positive association between KL grades and vertebral fractures.
  
  
  CONCLUSIONS
  Despite high systemic BMD, knee osteoarthritis was positively associated with VFs. These results suggest that bone quality, and consequently bone strength, may be decreased at the systemic level in knee osteoarthritis.
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, Haeundae Paik Hospital, College of Medicine, Inje University , Haeundae-gu Jwa-dong 1435 Busan , South Korea . e-mail: junjan@paik.ac.kr , sglee@paik.ac.kr.
authors.forename: Sunggun
authors.initials: S
authors.lastname: Lee
authors.forename: Tae-Nyun
authors.initials: TN
authors.lastname: Kim
authors.forename: Seong-Ho
authors.initials: SH
authors.lastname: Kim
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People; D015519:Bone Density / Q000502:physiology*; D003430:Cross-Sectional Studies; D005260:Female; D005272:Femur Neck / Q000000981:diagnostic imaging / Q000293:injuries*; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000293:injuries*; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000453:epidemiology*; D015995:Prevalence; D011859:Radiography; D012307:Risk Factors; D016103:Spinal Fractures / Q000000981:diagnostic imaging / Q000453:epidemiology*