Maintenance vitamin D3 dosage requirements in Chinese women with post menopausal osteoporosis living in the tropics.
Asia Pac J Clin Nutr. 2017 May;26(3):412-420. doi: 10.6133/apjcn.042016.10.
Venugopal Y1, Hatta SFWM2, Musa N2, Rahman SA2, Ratnasingam J2, Paramasivam SS2, Lim LL2, Ibrahim L2, Choong K2, Tan AT2, Chinna K2, Chan SP2, Vethakkan SR2.
- 1 Department of Medicine, University of Malaya, Lembah Pantai,59100 Kuala Lumpur,Malaysia. Email: email@example.com; firstname.lastname@example.org.
- 2 Department of Medicine, University of Malaya, Lembah Pantai,59100 Kuala Lumpur,Malaysia.
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Notes by VitaminDWiki
- Mean of 43 nanograms at 4 months
Thus half > 43 ng and half < 43 ng
- Vitamin D levels probably still rising at 6 months (no data)
BACKGROUND AND OBJECTIVES:
Vitamin D3 (cholecalciferol) dose required to maintain sufficiency in non- Caucasian women with postmenopausal osteoporosis (PMO) inthe tropics has not been well studied. Some guidelines mandate 800-1000 IU vitamin D/day but the Endocrine Society (US) advocates 1500-2000 IU/day to maintain 25-hydroxyvitamin-D (25(OH)D) concentration at >75 nmol/L. We aimed to establish oral cholecalciferol dose required to maintain 25(OH)D concentration at >75 nmol/L in PMO Chinese Malaysian women, postulating lower dose requirements amongst light-skinned subjects in the tropics.
METHODS AND STUDY DESIGN:
90 Chinese Malaysian PMO women in Kuala Lumpur, Malaysia (2°30'N) with baseline serum 25(OH)D levels >=50 nmol/L were recruited. Prior vitamin D supplements were discontinued and subjects randomized to oral cholecalciferol 25,000 IU/4-weekly (Group-A) or 50,000 IU/4-weekly (Group- B ) for 16 weeks, administered under direct observation. Serum 25(OH)D, PTH, serum/urinary calcium were measured at baseline, 8 and 16 weeks.
Baseline characteristics, including osteoporosis severity, sun exposure (~3 hours/week), and serum 25(OH)D did not differ between treatment arms. After 16 weeks, 91% of women sufficient at baseline, remained sufficient on 25,000 IU/4-weekly compared with 97% on 50,000 IU/4-weekly with mean serum 25(OH)D 108.1±20.4 and 114.7±18.4 SD nmol/L respectively (p=0.273). At trial's end, 39% and 80% of insufficient women at baseline attained sufficiency in Group A and Group B (p=0.057). Neither dose was associated with hyperparathyroidism or toxicity.
Despite pretrial vitamin D supplementation and adequate sun exposure, 25.6% Chinese Malaysian PMO women were vitamin D insufficient indicating sunshine alone cannot ensure sufficiency in the tropics. Both ~900 IU/day and ~1800 IU/day cholecalciferol can safely maintain vitamin D sufficiency in >90% of Chinese Malaysian PMO women. Higher doses are required with baseline concentration <75 nmol/L.