Inclusion Criteria:  Post-menopausal women between 55 and 75 years  Exclusion Criteria:  Severely impaired renal function Severely impaired hepatic function Coagulation factors PP<0.6 Hypercalcemia (p-ion calcium >1.32 nmol/l) Previous or present malignancies (except a treated skin cancer that is not melanoma or treated carcinoma in situ, 2 years since last therapy) Diseases affecting the calcium homeostasis including untreated thyroid diseases Regular use of medicine affecting the calcium homeostasis, including diuretics, fenemal, lithium, antiepileptica and glucosteroids Selective serotonin reuptake inhibitor (SSRI)-products with fluvoxamin Treatment with carbamazepin Treatment with rifampicin Severe malabsorption syndrome including gastric or intestinal resection Alcohol or drug abuse Smokers