Fig. 3

Plots of unadjusted specific intrinsic fluorescence (SIF by SCOUT DS) vs. unadjusted LW-1 (left) and unadjusted collagen-linked fluorescence/CLF (right) in DCCT/EDIC participants (see “Methods”). LW-1 and CLF were assayed in enzymatic digests of insoluble collagen prepared from skin biopsies obtained from the buttock region of participants at DCCT closeout (1993). SIF was obtained by noninvasive measurements of autofluorescence made by the SCOUT DS on the underside of the left forearm skin near the elbow for most DCCT participants at EDIC years 16–17 (2009–2010). Regression line and 95 % CI prediction: CLF y = 141 + 2.1x, r = 0.209, P = 0.004, n = 185; LW-1: y = 195 + 8.9x, r = 0.25, P = 0.001, n = 185. Symbols used: see Fig. 1