title: Serum 1,25-dihydroxy vitamin D is inversely associated with body mass index.
abstract: BACKGROUND
  Based on in vitro studies, it has been hypothesized that 1,25-dihydroxy vitamin D (1,25-vit D) may promote weight gain in humans, but previous studies have demonstrated conflicting results regarding the association between serum 1,25-vit D and body mass index (BMI).
  
  
  OBJECTIVE
  To evaluate the relation between serum 1,25-vit D and BMI.
  
  
  METHODS
  Two thousand one hundred and eighty-seven subjects, recruited from a metabolic and medical lifestyle management clinic, were included in a cross-sectional study. BMI, 25-hydroxy vitamin D (25-OH-vit D) and 1,25-vit D were measured. The cohort was divided according to BMI in five groups (<25, 25-29.9, 30-34.9, 35-39.9 and >39.9 kg/m(2)). Statistical analyses were performed with multiple linear regression models. Age and gender were used as explanatory covariates.
  
  
  RESULTS
  With increasing BMI group, there was a significant decrease in both serum 25-OH-vit D and 1,25-vit D (P<0.001). Those with BMI >39.9 kg/m(2) had 24% lower serum 25-OH-vit D levels and 18% lower 1,25-vit D levels than those with BMI <25 kg/m(2).
  
  
  CONCLUSIONS
  There is an inverse association between BMI and the serum levels of 25-OH-vit D and 1,25-vit D. This makes it highly unlikely that high levels of circulating 1,25-vit D contribute to the development of obesity.
authors.affiliation: Institute of Clinical Medicine, University of Tromsø, Tromsø, Norway.
authors.forename: Steinar
authors.initials: S
authors.lastname: Konradsen
authors.forename: Harald
authors.initials: H
authors.lastname: Ag
authors.forename: Fedon
authors.initials: F
authors.lastname: Lindberg
authors.forename: Sofie
authors.initials: S
authors.lastname: Hexeberg
authors.forename: Rolf
authors.initials: R
authors.lastname: Jorde
mesh_terms: D000328:Adult; D000367:Age Factors; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood*; D012737:Sex Factors; D013851:Thinness / Q000097:blood; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D014807:Vitamin D; C097949:1,25-dihydroxyvitamin D; C104450:25-hydroxyvitamin D