title: Predictors of vitamin D biochemical status in a large sample of middle-aged male smokers in Finland.
abstract: OBJECTIVE
  As vitamin D deficiency is considered to be more common in regions with little solar ultraviolet (UV) light in winter, the aim of this study was to analyze predictors of vitamin D status by season within a large sample of male smokers from Finland, a country where there is negligible solar UV light in winter.
  
  
  METHODS
  Vitamin D (measured by 25-hydroxyvitamin D (25(OH)D) nmol/l) and other serum constituents were assayed. Measured anthropometry, and self-reported dietary intake and physical activity (PA) were obtained and analyzed using stepwise multiple linear and logistic regression in 2271 middle-aged Finnish male smokers.
  
  
  RESULTS
  In all, 27% of the population in winter and 17% in summer had serum 25(OH)D levels of <25 nmol/l, respectively. In summer, in multiple logistic regression analyses with adjustment for confounding and other predictors, high vitamin D intake (odds ratios (OR) 3.6; 95% confidence interval (CI) 1.5-8.5), some leisure time PA (OR 2.0; 95% CI 1.3-3.1) and having a body mass index (BMI) of >or=21 kg/m(2) compared with <21 kg/m(2) (OR 2.6; 95% CI 1.3-5.0), were associated with 25(OH)D >or=25 nmol/l. In winter, additional modifiable factors were occupational PA (OR 1.6; 95% CI 1.1-2.5) and high fish (OR 3.1; 95% CI 1.7-6.2) or poultry consumption (OR 1.7; 95% CI 1.2-2.5). Predictors from linear regression analyses of continuous levels of 25(OH)D were similar to the logistic regression analyses of 25(OH)D >or=25 nmol/l.
  
  
  CONCLUSIONS
  In this Finnish sample more vitamin D intake, PA and having a BMI of >or=21 may have important modifiable roles in maintaining an adequate vitamin D status.
authors.affiliation: Faculty of Health Sciences, University of Sydney, New South Wales, Australia. Kaye.Brock@Sydney.edu.au
authors.forename: K E
authors.initials: KE
authors.lastname: Brock
authors.forename: B I
authors.initials: BI
authors.lastname: Graubard
authors.forename: D R
authors.initials: DR
authors.lastname: Fraser
authors.forename: S J
authors.initials: SJ
authors.lastname: Weinstein
authors.forename: R Z
authors.initials: RZ
authors.lastname: Stolzenberg-Solomon
authors.forename: U
authors.initials: U
authors.lastname: Lim
authors.forename: J A
authors.initials: JA
authors.lastname: Tangrea
authors.forename: J
authors.initials: J
authors.lastname: Virtamo
authors.forename: L
authors.initials: L
authors.lastname: Ke
authors.forename: K
authors.initials: K
authors.lastname: Snyder
authors.forename: D
authors.initials: D
authors.lastname: Albanes
mesh_terms: D000368:Aged; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D015444:Exercise / Q000502:physiology; D005387:Finland; D006801:Humans; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009752:Nutritional Status; D011237:Predictive Value of Tests; D016032:Randomized Controlled Trials as Topic; D012307:Risk Factors; D017747:Seafood; D012621:Seasons; D012907:Smoking / Q000097:blood*; D014466:Ultraviolet Rays; D014807:Vitamin D / Q000008:administration & dosage / Q000096:biosynthesis / Q000097:blood*; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology*
chemical_list: D014807:Vitamin D