 A bone density test at screening and twelve months will allow us to assess the effect of vitamin D repletion on whole body bone mass and skeletal mass. At each GCRC stay, 3, 6 and 12 months, women will complete questionnaires regarding quality of life and functional status and will perform the Timed Up and Go Test. Because we wish to maintain and confirm constant calcium intake throughout the one- year study, women will complete a calcium questionnaire at baseline, 3, 6 and 12 months. 