Skin autofluorescence, a non-invasive biomarker of advanced glycation end products, and its relation to radiographic and MRI based osteoarthritis

Objectives: Accumulation of advanced glycation end products (AGEs) in articular cartilage during aging has been proposed as a mechanism involved in the development of osteoarthritis (OA). Therefore, we investigated a cross-sectional relationship between skin AGEs, a biomarker for systemic AGEs accumulation, and OA. Methods: Skin AGEs were estimated with the AGE Reader™ as skin autofluorescence (SAF). Knee and hip X-rays were scored according to Kellgren and Lawrence (KL) system. KL-sum score of all four joints was calculated per participant to assess severity of overall radiographic OA (ROA) including or excluding those with prosthesis. Knee MRI of tibiofemoral joint (TFMRI) was assessed for cartilage loss. Sex-stratified regression models were performed after testing interaction with SAF. Results: 2,153 participants were included for this cross-sectional analysis. In women (n = 1,206) for one unit increase in SAF, the KL-sum score increased by 1.15 (95% confidence interval = 1.00–1.33) but excluding women with prosthesis, there was no KL-sum score increase [0.96 (0.83–1.11)]. SAF was associated with higher prevalence of prosthesis [Odds ratio, OR = 1.67 (1.10–2.54)] but not with ROA [OR = 0.83 (0.61–1.14)] when compared to women with no ROA. In men (n = 947), there was inconclusive association between SAF and KL sum score or prosthesis. For TFMRI (n = 103 women), SAF was associated with higher prevalence of cartilage loss, full-thickness [OR = 5.44 (1.27–23.38)] and partial-thickness [OR = 1.45 (0.38–5.54)], when compared to participants with no cartilage loss. Conclusion: Higher SAF in women was associated with higher prosthesis prevalence and a trend towards higher cartilage loss on MRI. Our data presents inconclusive results between SAF and ROA in both sexes