Hyperzincuria in IDDM women. Relationship to measures of glycemic control, renal function, and tissue catabolism

Eighteen women with insulin-dependent diabetes mellitus (IDDM) and 15 nondiabetic women participated in a study of the relationship of zincuria to measures of glycemic control, renal function, and tissue catabolism. In the IDDM women, mean +/- SE glycosylated hemoglobin was 9.8 +/- 0.5%, and fasting plasma glucose was 189 +/- 19 mg/dl; duration of diabetes averaged 15 yr. In comparison with control women, the IDDM women excreted four times as much zinc in the urine. However, the total plasma zinc concentration was significantly higher in the IDDM than in the control women (14.7 vs. 13.4 microM). The increased urinary zinc loss in the IDDM women was not related to urine volume, urinary glucose excretion, fasting plasma glucose concentration, percent glycosylated hemoglobin, or an increased glomerular filtration rate. Total urinary protein losses were four times higher in the IDDM women than in the control women, and these urinary protein losses correlated with the urinary zinc losses (P less than .007). There was no relationship between urinary zinc and the excretion of any of the amino acids, urea, or ammonia. The results of this study show that hyperzincuria in diabetes is not associated with lower plasma zinc levels. An increased zinc absorption, decreased intestinal zinc excretion, or increased tissue catabolism may support higher plasma zinc levels.