title: Vitamin D status, bone mineral density, and the development of radiographic osteoarthritis of the knee: The Rotterdam Study.
abstract: OBJECTIVE
  To study the association between baseline vitamin D status, bone mineral density (BMD), and the development of radiographic osteoarthritis (ROA) of the knee in a large population-based cohort of men and women.
  
  
  METHODS
  A sample of 1248 subjects (728 women and 520 men) was drawn from the Rotterdam Study, a prospective population-based cohort study of the elderly. At baseline, vitamin D dietary intake was determined, and BMD and 25-hydroxy vitamin D (25(OH)D) serum levels were measured. After a mean follow-up time of 6.5 years incidence and progression of knee ROA of was assessed.
  
  
  RESULTS
  The mean vitamin D intake in our study population was 64 IU/d and the mean 25(OH)D level 66 nmol/L. Vitamin D levels were associated with baseline BMD, particularly in subjects with baseline knee ROA. Progressive ROA occurred in 5.1% of the participants in the highest tertile of vitamin D intake against 12.6% in the lowest tertile, resulting in an adjusted odds ratio of 7.7 (95% CI: 1.3-43.5). Both intake and levels of 25(OH)D were not significantly related to incident ROA. However, we found a significant interaction between vitamin D intake and BMD in the association with incident knee ROA (P = 0.03): in subjects with low lumbar spine BMD at baseline we observe an increasing incidence of knee ROA with decreasing vitamin D intake and serum levels.
  
  
  CONCLUSIONS
  Low dietary vitamin D intake increases the risk of progression of knee ROA. Particularly in subjects with low baseline BMD, vitamin D status seems to influence the incidence and progression of knee ROA. Thus, improving the vitamin D status in the elderly could protect against the development and worsening of knee OA, especially in those with low BMD.
authors: Departments of Internal Medicine, Erasmus Medical Center, Rotterdam 3000 DR, The Netherlands.
authors: Arjan P
authors: AP
authors: Bergink
authors: André G
authors: AG
authors: Uitterlinden
authors: Johannes P T M
authors: JP
authors: Van Leeuwen
authors: Cok J
authors: CJ
authors: Buurman
authors: Albert
authors: A
authors: Hofman
authors: Jan A N
authors: JA
authors: Verhaar
authors: Huibert A P
authors: HA
authors: Pols
mesh_terms: D000368:Aged; D015519:Bone Density; D001851:Bone Diseases, Metabolic / Q000150:complications*; D002112:Calcifediol / Q000097:blood*; D018450:Disease Progression; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D015596:Nutrition Assessment; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000209:etiology*; D011446:Prospective Studies; D011859:Radiography; D012307:Risk Factors; D014808:Vitamin D Deficiency / Q000150:complications*
chemical_list: D002112:Calcifediol