title: Determinants of Serum 25-Hydroxyvitamin D Concentrations and a Screening Test for Moderate-to-Severe Hypovitaminosis D in Chinese Patients Undergoing Total Joint Arthroplasty.
abstract: Hypovitaminosis D is associated with adverse surgical outcomes. We quantified the environmental, demographic, and modifiable determinants of serum 25-hydroxyvitamin D (25-OHD) concentration and assessed the potential impact of a preoperative screening questionnaire for moderate-to-severe hypovitaminosis D (25-OHD <30 nmol/L).
  
  
  
  In a retrospective cohort study of 227 Chinese patients (69 males and 158 females) undergoing 261 joint arthroplasty, we collected information on recent sun exposure, dietary vitamin D intake, vitamin D supplementation, and Western Ontario and McMaster Universities osteoarthritis index using a questionnaire and measured a fasting 25-OHD concentration using a liquid chromatography-tandem mass spectrometry before surgery.
  
  
  
  The multiple regression model on the determinants of 25-OHD concentration described 14% of the total variance, with the greatest relative contribution from ambient ultraviolet radiation (42%). A 4-item screening test for moderate-to-severe hypovitaminosis D had acceptable discrimination (area under receiver operating characteristic curve = 0.76, 95% CI, 0.65-0.87), good calibration (Hosmer-Lemeshow goodness-of-fit; P = .93). Decision curve analysis showed that the screening test can potentially reduce unnecessary 25-OHD testing by 390 per 1000 patients at a threshold probability of 10%.
  
  
  
  The screening test appears moderately useful in avoiding a substantial number of unnecessary 25-OHD testing in a setting where the prevalence of moderate-to-severe hypovitaminosis D is less than 10%.
authors.affiliation: Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, NT, Hong Kong.
authors.forename: Anna
authors.initials: A
authors.lastname: Lee
authors.affiliation: Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, NT, Hong Kong.
authors.forename: Winnie
authors.initials: W
authors.lastname: Samy
authors.affiliation: Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, NT, Hong Kong.
authors.forename: Chun Hung
authors.initials: CH
authors.lastname: Chiu
authors.affiliation: Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, NT, Hong Kong.
authors.forename: Simon Kin Cheong
authors.initials: SK
authors.lastname: Chan
authors.affiliation: Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, NT, Hong Kong.
authors.forename: Tony
authors.initials: T
authors.lastname: Gin
authors.affiliation: Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, NT, Hong Kong.
authors.forename: Po Tong
authors.initials: PT
authors.lastname: Chui
mesh_terms: D000368:Aged; D001178:Arthroplasty; D019643:Arthroplasty, Replacement; D019587:Dietary Supplements; D005260:Female; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D015999:Multivariate Analysis; D011300:Preoperative Care / Q000379:methods*; D015995:Prevalence; D012372:ROC Curve; D012189:Retrospective Studies; D011795:Surveys and Questionnaires; D014466:Ultraviolet Rays; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000175:diagnosis*
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: determinants; screening test; sunlight; total joint arthroplasty; vitamin D