Vit D injections were found to increase the 25OH Vit D  levels in patients with lower BMI levels less than 25 than in those with BMI more than 25.

Team@CMHF

OBJECTIVES: There is no protocol of vitamin D supplementation used worldwide due to a great disparity of vitamin D supplements available in different countries.

The aim of this study was to evaluate the efficiency of the protocol most often used in France to correct vitamin D deficiency defined by a serum 25-hydroxy vitamin D (25OHD) level of less than 30ng/mL. METHODS: This was a pragmatic multicentric study of vitamin D supplementation in 257 osteopenic/osteoporotic, vitamin D deficient patients who received 100,000UI vitamin D3 vials every two weeks according to their initial serum 25OHD level (four vials when 25OHD less than 10ng/mL, three when 25OHD was 10-19ng/mL, two when 25OHD was 20-29ng/mL). Blood samples were obtained at baseline, one (M1), two (M2), and three months (M3), after the end of the supplementation protocol. RESULTS: At M1, 198/257 (77%) patients had a serum 25OHD level more than 30ng/mL. Eighty-five percent of those with a BMI less than 25kg/m(2) had a 25OHD concentration more than 30ng/mL, whereas only 66% of those with a BMI more than 25 had a level more than 30ng/mL. At M2 and M3, 25OHD levels decreased significantly with 55% and 46% having still a level more than 30ng/mL respectively, without any significant difference according to the initial 25OHD level.

CONCLUSION: This protocol was effective in rising serum 25OHD of most vitamin D insufficient patients with a BMI less than 25kg/m(2), but not in overweight patients. As almost one half of our patients had a serum 25OHD level less than 30ng/mL at M2, we suggest that regular doses should be started quite soon after this initial supplementation.

Ref: http://www.docguide.com/vitamin-d-insufficiency-evaluation-oral-standardized-supplementation-using-100-000iu-vials-cholecalc