Br J Nutr. 2022 Aug 19:1-22. doi: 10.1017/S0007114522002641. Online ahead of print.
Vitamin D (VD) deficiency [serum 25(OH)D concentration of <20 ng/ml], in endemic proportions, demands a supplementation strategy with optimal dosing regimens. A randomised parallel-group, active-controlled trial was conducted among apparently healthy, VD deficient subjects, age 18-60 years who received 600 IU/day (Group A), 1000 IU/day (Group B), 2000 IU/day (Group C) and 60,000 IU/month (Group D) of oral cholecalciferol. The intervention was carried in two phases (I&II) of 12 weeks each, with same dose, separated by a washout phase of 12 weeks. Serum 25(OH)D, iPTH, calcium (Ca), phosphorous (PO4), alkaline phosphatase (ALP), spot urine calcium/creatinine (Ca/Cr) was measured at baseline, 12, 24 and 36 weeks following the intervention and adverse events were recorded at each occurrence and at 12, 24 and 36 weeks. A statistically significant time-group interaction was found in serum 25(OH)D concentration (P<0.05). Serum 25(OH)D concentration increased significantly from baseline to 12 weeks (P<0.05) in all the groups with no change at 24 weeks but further increase at 36 weeks (P<0.05). At the end of study, group C had maximum increment in serum 25(OH)D concentration while as groups C and D (95%, and 90%) had higher proportion of subjects VD sufficient than groups A and B (65% and 78%) (Table 3) (P<0.05). No significant time-dose interactions were observed in serum iPTH, Ca, PO4 and ALP or Urine Ca/Cr ratio. Three subjects (two in group C and one in group D) developed transient hypercalciuria. Supplementation with daily 2000IU or monthly 60,000IU oral cholecalciferol among adults seems optimal and safe.