Prevalence of Vitamin D inadequacy among postmenopausal North American women receiving osteoporosis therapy.
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.
Holick
Michael F
MF
Boston University School of Medicine, 715 Albany Street, M1013, Boston, Massachusetts 02118, USA. mfholick@bu.edu
Siris
Ethel S
ES
Binkley
Neil
N
Beard
Mary K
MK
Khan
Aliya
A
Katzer
Jennifer T
JT
Petruschke
Richard A
RA
Chen
Erluo
E
de Papp
Anne E
AE
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*
D010281:Parathyroid Hormone; D002112:Calcifediol