Influence of Alfacalcidol on Falls in Osteopenic/Osteoporotic Postmenopausal Women (ALFA Study)

Inclusion Criteria: * age \> 65 years * postmenopausal women * osteopenia/osteoporosis as defined by WHO criteria Exclusion Criteria: * Neoplasm or other severe diseases with life expectancy less than one year or expectation of rapid worsening within one year * Chronic inflammatory rheumatoid disease * Arthritis with continuous pain and influence on locomotion * Inflammatory or metabolic bone disease, excluding osteoporosis. * Subjects with antiosteoporotic medications who are not willing to switch over to alendronate treatment. Estrogen treatment can be continued * 25-OH-Vitamin D3 \< 12 ng/ml (12 ng/ml = 30 mmol/L) * Systemic corticosteroid treatments of more than one month within previous 12 months * Intolerability for alfacalcidol * Hypercalcaemia (\>2,7 mmol/l) * Milk alkali syndrome * Uncorrected, severe visual impairments * Creatinin \> 2.5 mg/dl (\>220 µmol/L)