Carbohydrate metabolism and capillary basement-membrane thickness in children. I. cross-sectional studies.
Thirty-nine children from three to 16 years of age were included in this study. Nineteen were diabetics, seven were "suspected" diabetics (with evidence of glucose intolerance but without repeated fasting hyperglycemia), and 13 were controls. Mean glucose disappearance rates (K) during intravenous glucose tolerance tests (IVGTTs) were 2.19 for the controls, 1.23 for the suspected diabetics, and 0.70 for 14 diabetics tested; the differences were statistically significant. Diabetics had the smallest and suspected diabetics the greatest plasma insulin responses during IVGTTs. Fasting plasma growth hormone (GH) varied widely. GH generally decreased or remained unchanged during IVGTTs, but two diabetics exhibited slight increases and two sustpected diabetics pronounced increases. Basement-membrane thickness (BMT) was examined in 42 quadriceps femoris needle biopsies. Average BMT (ABMT) and minimum BMT (MBMT) correlated well (r = 0.91). BMT did not correlate well with age or, in the diabetics, with duration of clinical disease. Diabetics had the greatest and controls the least mean ABMT and MBMT, but the differences were not statistically significant. High values (those exceeding mean control values by more than two standard deviations) were much more common among the suspected diabetics and the diabetics. One of 13 controls, three of six suspected diabetics, and six of 19 diabetics had high ABMT values; two suspected diabetics and five diabetics had high MBMT values. Correlations between BMT and K were negative for the most part, but correlation coefficients were small. Serial studies in four of the children suggest that BMT and glucose tolerance tend to change in opposite directions.