Endocrine Abstracts

Introduction: Severe vitamin D deficiency is very common in northern Europe. It is not limited to the elderly, but occurs in a large variety of subjects. Colecalciferol dosing guidelines for rapid correction of vitamin D deficiency are not available.

Objective: To assess the optimal Colecalciferol dose regimen, based on body weight, for rapid correction of vitamin D deficiency, in a variety of subjects.

Materials and methods: One hundred and twenty-three subjects (age ranging from 20 to 90 years, female/male ratio 1.9:1, body weight ranging from 41 to 175 kg) with vitamin D deficiency (defined as serum vitamin D level <50 nmol/l) were treated with solubilised Colecalciferol 50.000 E/ml, in a dose of 25.000 IU every 2 weeks during 8 weeks (total dose 100.000 IU), 25.000 IU every week during 6 weeks (total dose 150.000 IU), or 25.000 IU every week during 8 weeks (total dose 200.000 IU). The Colecalciferol dose per kilogram body weight ranged from 625 to 4000 IU/kg. Serum creatinine, calcium, phosphate, albumin, PTH, 25-OH-D₃ were measured at baseline and 10 days after the final dose of Colecalciferol.

Results: Mean 25-OHD₃ increased from 20.2±0.7 to 69.5±2.9 nmol/l (mean±S.E.M., P<0.0001). Serum calcium, phosphate, albumin and PTH levels did not change significantly. The Colecalciferol dose required to achieve the optimal serum level of 75 nmol/l was related to the vitamin D deficit (Δ25-OHD₃=75 – actual 25-OHD₃ level) and body weight. The dose per kg body weight required to achieve normalisation of serum 25-OHD₃ was:

Dose (IU/kg)=40 (Δ25-OHD₃)+400 (R²=0.42, P<0.0001).

Conclusion: Correction of vitamin D deficiency by Colecalciferol should be based on the degree of vitamin D deficit and body weight.