Objective: To determine the association between skin intrinsic fluorescence (SIF), a noninvasive measure of advanced glycation endproducts and oxidative stress in skin, and retinal microvascular complications of long duration type 1 diabetes, proliferative diabetic retinopathy (PDR) and macular edema.
Methods: A cross-sectional cohort study of persons with type 1 diabetes in the Wisconsin Epidemiologic Study of Diabetic Retinopathy (WESDR) who participated in a 32-year follow-up examination in 2012-2014. Subjects underwent a physical examination, answered a health questionnaire, and had fundus photographs taken. SIF was measured on the underside of the left forearm near the elbow with the SCOUT DS® skin fluorescence spectrometer. Two representative SIF measures were used for these analyses: SIF01 excited by an LED centered at 375 nm with correction factors Kx = 0.6 and Km = 0.2 and SIF15 excited by an LED centered at 456 nm with correction factors Kx = 0.4 and Km = 0.9.
Results: The 414 participants had mean diabetes duration of 42.2 years (standard deviation 6.8 years, range 32.9-67.9 years). PDR was statistically significantly associated (p < 0.05) with both SIF measures in multivariate models including other relevant factors (odds ratio [OR] = 1.17 for SIF01 and 1.20 for SIF15).
Conclusion: Skin intrinsic fluorescence measures are independently associated with PDR in the WESDR. Incidence information is needed to evaluate whether there is a causal relationship.
Keywords: Advanced glycation endproducts; macular edema; nephropathy; proliferative diabetic retinopathy; skin intrinsic fluorescence.