Association of Skin Intrinsic Fluorescence with Retinal Microvascular Complications of Long Term Type 1 Diabetes in the Wisconsin Epidemiologic Study of Diabetic Retinopathy.

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 (R) skin fluorescence spectrometer. Two representative SIF measures were used for these analyses: SIF01 excited by an LED centered at 375 nm with correction factors K-x = 0.6 and K-m = 0.2 and SIF15 excited by an LED centered at 456 nm with correction factors K-x = 0.4 and K-m = 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.