title: Determinants of vitamin D status in healthy men and women aged 40-80 years.
abstract: OBJECTIVE
  To determine the contribution of life style and health related factors on vitamin D status in middle-aged and older men and women.
  
  
  METHODS
  A cross-sectional single-center study in 400 male subjects (40-80 years) and 402 postmenopausal female subjects (56-73 years), conducted in a University Medical Center in the central part of the Netherlands (52 degrees northern latitude).
  
  
  METHODS
  Medical history, vitamin D, calcium and alcohol intake, physical activity, Body Mass Index, Blood pressure, smoking, total fat body mass and total lean body mass were measured using DEXA. Laboratory analysis included 25-hydroxyvitamin D (25OHD) and sex hormones.
  
  
  RESULTS
  Thirty-six percent of men and 51% of women had 25OHD less than 50 nmol/L. In summertime men had significant higher 25OHD as compared to women (81.5 vs 53.3 nmol/L, P=.000) but this difference disappeared come winter. In a saturated model, male gender (B=.16, P=.008), and season (summer vs winter B=.30, P=.000) remained statistically significant. In men, physical activity and season explained 21% of the variance. In women, household physical activity (B=.13, P=.03), sport physical activity (B=.02, P=.02) and estradiol (B=-.003, P=.048) remained in the model,.
  
  
  CONCLUSIONS
  In healthy middle-aged and older men and postmenopausal women, male gender and season were important predictors of vitamin D status. In men, physically activity and season, explained 21% of the variance in vitamin D status. In women, physical activity and estradiol explained 9.3% of the variance in vitamin D.
authors.affiliation: Department of Geriatrics, University Medical Center Utrecht, The Netherlands. hcjp.janssen@gmail.com
authors.forename: H C J P
authors.initials: HC
authors.lastname: Janssen
authors.forename: M H
authors.initials: MH
authors.lastname: Emmelot-Vonk
authors.forename: H J J
authors.initials: HJ
authors.lastname: Verhaar
authors.forename: Y T
authors.initials: YT
authors.lastname: van der Schouw
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D002908:Chronic Disease; D015444:Exercise; D005260:Female; D006801:Humans; D008019:Life Style; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D017698:Postmenopause; D012621:Seasons; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000175:diagnosis
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D