title: Vitamin D deficiency is associated with progression of knee osteoarthritis.
abstract: BACKGROUND
  Knee osteoarthritis causes functional limitation and disability in the elderly. Vitamin D has biological functions on multiple knee joint structures and can play important roles in the progression of knee osteoarthritis. The metabolism of vitamin D is regulated by parathyroid hormone (PTH).
  
  
  OBJECTIVE
  The objective was to investigate whether serum concentrations of 25-hydroxyvitamin D [25(OH)D] and PTH, individually and jointly, predict the progression of knee osteoarthritis.
  
  
  METHODS
  Serum 25(OH)D and PTH were measured at the 30- or 36-mo visit in 418 participants enrolled in the Osteoarthritis Initiative (OAI) who had ≥1 knee with both symptomatic and radiographic osteoarthritis. Progression of knee osteoarthritis was defined as any increase in the radiographic joint space narrowing (JSN) score between the 24- and 48-mo OAI visits.
  
  
  RESULTS
  The mean concentrations of serum 25(OH)D and PTH were 26.2 μg/L and 54.5 pg/mL, respectively. Approximately 16% of the population had serum 25(OH)D < 15 μg/L. Between the baseline and follow-up visits, 14% progressed in JSN score. Participants with low vitamin D [25(OH)D < 15 μg/L] had >2-fold elevated risk of knee osteoarthritis progression compared with those with greater vitamin D concentrations (≥15 μg/L; OR: 2.3; 95% CI: 1.1, 4.5). High serum PTH (≥73 pg/mL) was not associated with a significant increase in JSN score. However, participants with both low vitamin D and high PTH had >3-fold increased risk of progression (OR: 3.2; 95%CI: 1.2, 8.4).
  
  
  CONCLUSIONS
  Our results suggest that individuals deficient in vitamin D have an increased risk of knee osteoarthritis progression.
authors.affiliation: Department of Nutrition Science, Friedman School of Nutrition Science and Policy and Jean Mayer USDA Human Nutrition Research Center at Tufts University, Boston, MA fang_fang.zhang@tufts.edu.
authors.forename: Fang Fang
authors.initials: FF
authors.lastname: Zhang
authors.affiliation: Division of Rheumatology, and.
authors.forename: Jeffrey B
authors.initials: JB
authors.lastname: Driban
authors.affiliation: Section of Immunology, Allergy, and Rheumatology, Michael E. DeBakey Veterans Affairs Medical Center and Baylor College of Medicine, Houston, TX.
authors.forename: Grace H
authors.initials: GH
authors.lastname: Lo
authors.affiliation: Tufts Clinical and Translational Sciences Institute, Tufts University, Boston, MA Institute for Clinical Research and Health Policy Studies.
authors.forename: Lori Lyn
authors.initials: LL
authors.lastname: Price
authors.affiliation: Department of Nutrition Science, Friedman School of Nutrition Science and Policy and Jean Mayer USDA Human Nutrition Research Center at Tufts University, Boston, MA.
authors.forename: Sarah
authors.initials: S
authors.lastname: Booth
authors.affiliation: Department of Family Medicine and Epidemiology, Alpert Medical School of Brown University, Center for Primary Care and Preventive, Pawtucket, RI.
authors.forename: Charles B
authors.initials: CB
authors.lastname: Eaton
authors.affiliation: Division of Rheumatology, Brigham and Women's Hospital and Harvard School of Medicine, Boston, MA.
authors.forename: Bing
authors.initials: B
authors.lastname: Lu
authors.affiliation: Department of Epidemiology and Biostatistics, University of California at San Francisco, San Francisco, CA.
authors.forename: Michael
authors.initials: M
authors.lastname: Nevitt
authors.affiliation: Division of Endocrinology, Diabetes, and Metabolism, Ohio State University Waxner Medical Center, Columbus, OH.
authors.forename: Becky
authors.initials: B
authors.lastname: Jackson
authors.affiliation: Department of Pathology and Laboratory Medicine, Tufts Medical Center, Boston, MA.
authors.forename: Cheryl
authors.initials: C
authors.lastname: Garganta
authors.affiliation: Department of Medicine and Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD; and.
authors.forename: Marc C
authors.initials: MC
authors.lastname: Hochberg
authors.affiliation: Division of Rheumatology and Clinical Immunology, University of Pittsburgh, Pittsburgh, PA.
authors.forename: Kent
authors.initials: K
authors.lastname: Kwoh
authors.affiliation: Division of Rheumatology, and.
authors.forename: Timothy E
authors.initials: TE
authors.lastname: McAlindon
mesh_terms: D000368:Aged; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007719:Knee Joint / Q000187:drug effects / Q000473:pathology; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000097:blood* / Q000150:complications / Q000188:drug therapy; D010281:Parathyroid Hormone / Q000097:blood; D012307:Risk Factors; D014807:Vitamin D / Q000008:administration & dosage / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood* / Q000150:complications / Q000188:drug therapy
chemical_list: D010281:Parathyroid Hormone; D014807:Vitamin D
keywords: Vitamin D; joint space narrowing; knee osteoarthritis; parathyroid hormone; progression