High Dosage Vitamin D and Osteoporosis

Inclusion Criteria: * bone mineral density in L2-4 or mean total hip with T-score \<= -2.0 Exclusion Criteria: * current use of bisphosphonates, PTH-analogs, estrogen, SERM, p.o. steroids or use of any of these agents last year * serum creatinin \>110 umol/L * systolic blood pressure \>175 mmHg or diastolic blod pressure \>105 * serious disease (heart failure, angina pectoris, myocardial infarction, diabetes, mental reduction, granulomatous disease like sarcoidosis, cancer) * kidney stone * serum calcium \> 2.55 mmol/L * suspect primary hyperparathyroidism with serum calcium \>2.50 mmol/L combined with PTH \> 5.0 mmol/L or serum calcium \> 2.45 mmol/L combined with PTH \>= 7.0 pmol/L