IMPROVEMENT IN GLUCOSE-TOLERANCE AND BETA-CELL FUNCTION IN A PATIENT WITH VITAMIN-D DEFICIENCY DURING TREATMENT WITH VITAMIN-D

Glucose metabolism was studied in a patient with vitamin D deficiency during its treatment with small doses of vitamin D. A continuous infus ion of glucose test was performed to assess glucose tolerance and insu lin sensitivity and beta-cell function were derived by mathematical mo delling. Fasting glucose was 5.6 mmol/l and achieved glucose after the infusion was 10.4 mmol/l confirming diabetes. The test was repeated 0 .5, 1, 3 and 5 months after starting treatment. Serum calcium increase d glucose intolerance from 1.76 to 2.0, 2.08, 1.96 and 2.0 mmol/l, res pectively; vitamin D reached supraphysiological levels initially and r eturned to normal levels, and parathyroid hormone levels were normaliz ed. Her weight did not change during treatment. Glucose tolerance impr oved during treatment and achieved glucose was 9.4, 8.6, 9.2 and 9.0 m mol/l at 0.5, 1, 3 and 5 months, respectively; insulin sensitivity did not change. Beta-cell function improved from 101% at diagnosis to 126 %, 147%, 173% and 198% at 0.5, 1, 3 and 5 months, respectively. Improv ement in beta-cell function and consequently in glucose tolerance is l ikely to have been due to correction of hypocalcaemia, vitamin D defic iency and secondary hyperparathyroidism.