Efficacy of daily and monthly high-dose calciferol in vitamin D-deficient nulliparous and lactating women.
BACKGROUND
We previously found a high prevalence of vitamin D deficiency and low medication regimen compliance in Arab and East Indian women residing in the United Arab Emirates (UAE). The appropriate dosing regimen for improving vitamin D status in this population is not known.


OBJECTIVE
We aimed to determine the efficacy of daily and monthly supplementation with vitamin D2, the only high-dose calciferol available in the UAE, in lactating and nulliparous women.


METHODS
Healthy lactating (n = 90) and nulliparous (n = 88) women were randomly assigned to consume 2000 IU vitamin D2/d or 60,000 IU vitamin D2/mo for 3 mo. Serum 25-hydroxyvitamin D [25(OH)D] concentrations were measured by radioimmunoassay at baseline and every month.


RESULTS
Most women had vitamin D deficiency [ie, 25(OH)D < 50 nmol/L] at study entry. Mean +/- SD 25(OH)D concentrations at 3 mo were significantly higher than baseline in both lactating (39.8 +/- 12.4 and 25.2 +/- 10.7 nmol/L, respectively) and nulliparous (40.4 +/- 23.4 and 19.3 +/- 12.2 nmol/L, respectively) women (P < 0.001 for both). In total, vitamin D supplementation was effective in achieving serum 25(OH)D concentrations of >or=50 nmol/L in 21 (30%) of 71 women at endpoint.


CONCLUSIONS
Oral vitamin D2 supplementation with 2000 IU/d or 60,000 IU/mo for 3 mo was safe, and it increased serum 25(OH)D concentrations significantly; however, only a small proportion of the women studied achieved concentrations of >or=50 nmol/L. This suggests that, when sunlight exposure is limited, doses of vitamin D2 higher than those currently studied may be needed. Monthly dosing appears to be a safe and effective alternative to daily dosing.
Saadi
Hussein F
HF
Department of Internal Medicine and Community Medicine, Faculty of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates. saadih@uaeu.ac.ae
Dawodu
Adekunle
A
Afandi
Bachar O
BO
Zayed
Reem
R
Benedict
Sheela
S
Nagelkerke
Nicolaas
N
D000284:Administration, Oral; D000328:Adult; D000704:Analysis of Variance; D018912:Arabs; D002118:Calcium / Q000097:blood / Q000652:urine; D004872:Ergocalciferols / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D007194:India / Q000208:ethnology; D007774:Lactation / Q000502:physiology; D010298:Parity; D011247:Pregnancy; D014808:Vitamin D Deficiency / Q000188:drug therapy* / Q000208:ethnology
D004872:Ergocalciferols; D002118:Calcium