A PROSPECTIVE STUDY OF COMMONLY UTILIZED REGIMENS OF VITAMIN D REPLACEMENT AND MAINTENANCE THERAPY IN ADULTS.

OBJECTIVE

To determine which vitamin D dose, formulation, and schedule most effectively and safely achieves a 25-hydroxyvitamin D (25[OH]D) level of >30 ng/mL (75 nmol/L).

METHODS

In this prospective study, 100 subjects from the NY Harbor HCS Brooklyn Campus, ages 25 to 85 years, with 25(OH)D <30 ng/mL (<75 nmol/L), were randomized into four groups: cholecalciferol (D3) 2,000 international units (IU) daily; D3 3,000 IU daily; ergocalciferol (D2) 50,000 IU weekly; and D2 50,000 IU twice weekly. All were supplemented with 500 mg calcium carbonate daily. 25(OH)D, parathyroid hormone (PTH), urinary calcium, urinary creatinine, and other variables were measured during 7 visits over 12 months.

RESULTS

All groups achieved a mean vitamin D level >30 ng/mL (>75 nmol/L) by visit 4 (5 months). Those receiving 50,000 IU D2 twice weekly displayed the most rapid and robust response, with 25(OH)D reaching >30 ng/mL (>75 nmol/L) after only 1 month and plateauing at 60 ng/mL (150 nmol/L) by 7 months. Although no statistically significant difference was seen in mean 25(OH)D levels between groups 1 through 3, subjects on 50,000 IU D2 weekly more consistently showed higher mean levels than either groups 1 or 2. No episodes of significant hypercalcemia occurred. There was a negative correlation in mean PTH levels and mean vitamin D levels in group 4 and all groups combined.

CONCLUSION

All four schedules of vitamin D replacement were effective in safely achieving and maintaining 25(OH)D >30 ng/mL (>75 nmol/L). D2 50,000 IU twice weekly provided the most rapid attainment and highest mean levels of vitamin D.

ABBREVIATIONS

25(OH)D = 25-hydroxyvitamin D; BMI = body mass index; BUN = blood urea nitrogen; Ca/Cr = calcium/creatinine; D2 = ergocalciferol; D3 = cholecalciferol; IU = international units; PTH = parathyroid hormone.