PTH and Hyperglycemia: To test the hypothesis that polyuria secondary to hyperglycemia leads to excess urinary calcium excretion, we investigated whether average glycemia modulated the effect of calcium intake on PTH in those with T1D by stratifying at the median HbA1c value (T1D Low = A1c <8.5%, T1D high = A1c ≥ 8.5%; n = 29 versus n = 32, respectively).