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 achieved a 25-hydroxy vitamin D (25OHD) level of > 30 ng/mL (75 nmol/L).

METHODS: In this prospective study, 100 subjects from the NY Harbor HCS Brooklyn Campus, ages 25-85 years old, with 25OHD <30 ng/mL (<75 nmol/L), were randomized into 4 groups: cholecalciferol (D3) 2,000 IU daily, D3 3,000 IU daily, ergocalciferol (D2) 50,000 IU weekly and D2 50,000 IU twice weekly. All were supplemented with 500mg calcium carbonate daily. 25OHD, 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 D2 twice weekly displayed the most rapid and robust response, 25OHD 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 statistical difference was seen in mean 25OHD levels between groups 1-3, subjects on 50,000 D2 weekly more consistently showed higher mean levels than either groups 1 and 2. No episodes of significant hypercalcemia occurred. There was a negative correlation in mean parathyroid hormone (PTH) levels and mean vitamin D levels in group 4, and all groups combined.

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

ABBREVIATIONS: 25(OH)D = 25-hydroxyvitamin D; BUN = blood urea nitrogen; Ca/Cr = Calcium/Creatinine, D2 = ergocalciferol; D3 = cholecalciferol; EGFR = estimated glomerular filtration rate; BMI = body mass index; PTH = parathyroid hormone; IU = international units; UV-B = ultraviolet B-rays.