- Because cancer and other autoimmune diseases may be more frequent in individuals with a moderate deficiency of vitamin D, subjects with a history of these conditions will be excluded. Because of the remote possibility of vitamin D-induced hypercalcemia, we are aiming at recruiting patients with RA who are otherwise healthy. We will exclude patients who in the past had or currently have cancer (except if considered cured), kidney stones, chronic renal failure, congestive heart failure, arrythmia requiring treatment with antiarrythmics, pulmonary conditions requiring ambulatory oxygen, abnormal levels of calcium or elevated PTH.