Correlations between skin intrinsic fluorescence and (A) biceps tendon thickness, measured in the bicipital groove (DM group: r=.44, P=.02); (B) peak humerothoracic elevation (DM group: r=−.44, P=.02); and (C) Disability of the Arm, Shoulder and Hand (DASH) questionnaire scores (DM group: r=.51, P=.009). Data points for the control group are included for comparison of distribution. Data analyzed for DM group using Pearson product moment correlation coefficients. DM=diabetes mellitus, AU=arbitrary units.