title: Association between serum concentration of 25-hydroxyvitamin D and the risk of hip arthroplasty for osteoarthritis: result from a prospective cohort study.
abstract: OBJECTIVE
  There is ongoing debate regarding the optimal serum concentrations of 25-hydroxy-vitamin D for musculoskeletal health, including osteoarthritis (OA). The aim of this prospective cohort study was to determine whether serum 25-hydroxy-vitamin D concentrations were associated with the risk of hip arthroplasty for OA.
  
  
  METHODS
  This study examined 9135 participants from the Australian Diabetes, Obesity and Lifestyle Study who had serum 25-hydroxy-vitamin D measured in 1999-2000 and were aged ≥40 years at the commencement of arthroplasty data collection. The incidence of hip arthroplasty for OA during 2002-2011 was determined by linking cohort records to the Australian Orthopaedic Association National Joint Replacement Registry.
  
  
  RESULTS
  Over an average 9.1 (standard deviation (SD) 2.7) years of follow-up, 201 hip arthroplasties for OA were identified (males n = 90; females n = 111). In males, a one-standard-deviation increase in 25-hydroxy-vitamin D was associated with a 25% increased incidence (HR 1.25, 95% CI 1.02-1.56), with a dose response relationship evident by quartiles of 25-hydroxy-vitamin D concentration (P for trend 0.04). These results were independent of age, body mass index (BMI), ethnicity, smoking status, physical activity, season of blood collection, latitude, hypertension and diabetes, area level disadvantage or after excluding those with extreme low 25-hydroxy-vitamin D concentrations. No significant association was observed in women (HR 1.10, 95% CI 0.87, 1.39).
  
  
  CONCLUSIONS
  Increasing serum 25-hydroxy-vitamin D concentrations were associated with an increased risk of hip arthroplasty for OA in males, while no significant association was observed in females. The mechanism for the association warrants further investigation.
authors.affiliation: Department of Epidemiology and Preventive Medicine, School of Public Health and Preventive Medicine, Monash University, Alfred Hospital, Melbourne, VIC 3004, Australia. Electronic address: monira.hussain@monash.edu.
authors.forename: S M
authors.initials: SM
authors.lastname: Hussain
authors.affiliation: Centre for Physical Activity and Nutrition Research, School of Exercise and Nutrition Sciences, Deakin University, Melbourne, VIC 3125, Australia; NorthWest Academic Centre, University of Melbourne, Western Health, St. Albans, VIC 3021, Australia. Electronic address: robin.daly@deakin.edu.au.
authors.forename: R M
authors.initials: RM
authors.lastname: Daly
authors.affiliation: Department of Epidemiology and Preventive Medicine, School of Public Health and Preventive Medicine, Monash University, Alfred Hospital, Melbourne, VIC 3004, Australia. Electronic address: yuanyuan.wang@monash.edu.
authors.forename: Y
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Baker IDI Heart and Diabetes Institute, Melbourne, VIC 3004, Australia. Electronic address: jonathan.shaw@bakeridi.edu.au.
authors.forename: J E
authors.initials: JE
authors.lastname: Shaw
authors.affiliation: Baker IDI Heart and Diabetes Institute, Melbourne, VIC 3004, Australia. Electronic address: dianna.magliano@bakeridi.edu.au.
authors.forename: D J
authors.initials: DJ
authors.lastname: Magliano
authors.affiliation: Australian Orthopaedic Association National Joint Replacement Registry, Discipline of Public Health, School of Population Health & Clinical Practice, University of Adelaide, SA 5005, Australia. Electronic address: segraves@aoanjrr.org.au.
authors.forename: S
authors.initials: S
authors.lastname: Graves
authors.affiliation: Department of Medicine, School of Clinical Science, Monash University, Melbourne, VIC 3168, Australia. Electronic address: peter.ebeling@monash.edu.
authors.forename: P R
authors.initials: PR
authors.lastname: Ebeling
authors.affiliation: Department of Epidemiology and Preventive Medicine, School of Public Health and Preventive Medicine, Monash University, Alfred Hospital, Melbourne, VIC 3004, Australia. Electronic address: anita.wluka@monash.edu.
authors.forename: A E
authors.initials: AE
authors.lastname: Wluka
authors.affiliation: Department of Epidemiology and Preventive Medicine, School of Public Health and Preventive Medicine, Monash University, Alfred Hospital, Melbourne, VIC 3004, Australia. Electronic address: flavia.cicuttini@monash.edu.
authors.forename: F M
authors.initials: FM
authors.lastname: Cicuttini
mesh_terms: D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000706:statistics & numerical data*; D001315:Australia; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D006801:Humans; D016247:Information Storage and Retrieval; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000097:blood / Q000601:surgery*; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012042:Registries; D012307:Risk Factors; D012737:Sex Factors; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: 25-Hydroxy-vitamin D; Hip arthroplasty; Osteoarthritis