Vitamin D – 50,000 IU monthly is enough if near the equator and have normal weight

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: yogesvenugopal@gmail.com; theyoges@hotmail.com.

• 2 Department of Medicine, University of Malaya, Lembah Pantai,59100 Kuala Lumpur,Malaysia.

The women only weighed 53 kg = 117 lbs; much more vitamin D is needed for heavier women 80% of the women had > 30 ng level of vitamin D - got 2.5 hours/week of sun - all year long + taking vitamin D supplements 1. Vitamin D levels around the world (30 ng is rare ) click on chart for details

📄 Download the PDF from VitaminDWiki

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.

RESULTS:

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.

CONCLUSIONS:

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.