title: Effects of age and renal function on vitamin D status in men.
abstract: BACKGROUND
  In general, no study has examined the relationship between vitamin D status and key parameters of bone mineral homeostasis in healthy men in Iran. The effects of age and renal function on vitamin D status were determined in a cross-sectional study on a healthy population of Iranian men.
  
  
  METHODS
  From January through February 2001, 520 men, aged 20 - 74 years were selected through a cluster randomized sampling from Shiraz. Serum 25-hydroxyvitamin D, intact parathyroid hormone, calcium, phosphorus, alkaline phosphatase, creatinine, and albumin were measured. Pearson and partial correlation coefficients were used to determine the association between variables.
  
  
  RESULTS
  Five hundred twenty men with a mean+/-SD age of 45+/-15 years and a mean+/-SD 25-hydroxyvitamin D level of 35+/-17 nmol/L were enrolled into the study. Over 33.9% of men in Shiraz had a low level of 25-hydroxyvitamin D (<or=25 nmol/L). Serum 25-hydroxyvitamin D did not decline with age in men. Serum parathyroid hormone increased significantly by age in men, but it did not correlate with the decline in creatinine clearance. Men had a decline in serum phosphorus (r=0.23, P<0.0001) and calcium (r=0.14, P=0.001) concentrations by age. Creatinine clearance declined with age.
  
  
  CONCLUSIONS
  In healthy men, the serum level of 25-hydroxyvitamin D did not decline with age. Nonetheless, the prevalence of vitamin D deficiency is high which warrants consideration of dietary vitamin D supplement in men.
authors.affiliation: Endocrine and Metabolism Research Center, Nemazee Hospital, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Seyed-Masoom
authors.initials: SM
authors.lastname: Masoompour
authors.forename: Abdossamad
authors.initials: A
authors.lastname: Sadegholvaad
authors.forename: Bagher
authors.initials: B
authors.lastname: Larijani
authors.forename: Gholamhossien
authors.initials: G
authors.lastname: Ranjbar-Omrani
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D003430:Cross-Sectional Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D055815:Young Adult
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D