title: Prevalence of Vitamin D inadequacy among postmenopausal North American women receiving osteoporosis therapy.
abstract: OBJECTIVE
  To evaluate serum 25-hydroxyvitamin D [25(OH)D] concentrations and factors related to vitamin D inadequacy in postmenopausal North American women receiving therapy to treat or prevent osteoporosis.
  
  
  METHODS
  Serum 25(OH)D and PTH were obtained in 1536 community-dwelling women between November 2003 and March 2004. Multivariate logistic regression was used to assess risk factors for suboptimal (<30 ng/ml) 25(OH)D.
  
  
  RESULTS
  Ninety-two percent of study subjects were Caucasian, with a mean age of 71 yr. Thirty-five percent resided at or above latitude 42 degrees north, and 24% resided less than 35 degrees north. Mean (sd) serum 25(OH)D was 30.4 (13.2) ng/ml: serum 25(OH)D was less than 20 ng/ml in 18%; less than 25 ng/ml in 36%; and less than 30 ng/ml in 52%. Prevalence of suboptimal 25(OH)D was significantly higher in subjects who took less than 400 vs. 400 IU/d or more vitamin D. There was a significant negative correlation between serum PTH concentrations and 25(OH)D. Risk factors related to vitamin D inadequacy included age, race, body mass index, medications known to affect vitamin D metabolism, vitamin D supplementation, exercise, education, and physician counseling regarding vitamin D.
  
  
  CONCLUSIONS
  More than half of North American women receiving therapy to treat or prevent osteoporosis have vitamin D inadequacy, underscoring the need for improved physician and public education regarding optimization of vitamin D status in this population.
authors.affiliation: Boston University School of Medicine, 715 Albany Street, M1013, Boston, Massachusetts 02118, USA. mfholick@bu.edu
authors.forename: Michael F
authors.initials: MF
authors.lastname: Holick
authors.forename: Ethel S
authors.initials: ES
authors.lastname: Siris
authors.forename: Neil
authors.initials: N
authors.lastname: Binkley
authors.forename: Mary K
authors.initials: MK
authors.lastname: Beard
authors.forename: Aliya
authors.initials: A
authors.lastname: Khan
authors.forename: Jennifer T
authors.initials: JT
authors.lastname: Katzer
authors.forename: Richard A
authors.initials: RA
authors.lastname: Petruschke
authors.forename: Erluo
authors.initials: E
authors.lastname: Chen
authors.forename: Anne E
authors.initials: AE
authors.lastname: de Papp
mesh_terms: D000058:Accidental Falls / Q000706:statistics & numerical data; D000203:Activities of Daily Living; D002112:Calcifediol / Q000097:blood / Q000172:deficiency; D003710:Demography; D004522:Educational Status; D005260:Female; D050723:Fractures, Bone / Q000453:epidemiology; D006304:Health Status; D006801:Humans; D007182:Income; D008875:Middle Aged; D009656:North America / Q000453:epidemiology; D015663:Osteoporosis, Postmenopausal / Q000188:drug therapy* / Q000517:prevention & control; D010281:Parathyroid Hormone / Q000097:blood; D015995:Prevalence; D012044:Regression Analysis; D012307:Risk Factors; D014808:Vitamin D Deficiency / Q000453:epidemiology*
chemical_list: D010281:Parathyroid Hormone; D002112:Calcifediol