Relevance of the oxidative balance score and red cell distribution width/albumin ratio in diabetic retinopathy: A mediation analysis in the NHANES

Background: As a comprehensive indicator of the body's overall oxidative stress status, the oxidative balance score (OBS) can reflect the body's antioxidant capacity and is associated with a myriad of diabetes-related complications. The red cell distribution width/albumin ratio (RAR) is recognized as a novel indicator of diabetes-related complications. At present, no studies have yet revealed the relationships among OBS, RAR and diabetic retinopathy (DR). We aimed to elucidate the relationship between OBS and DR risk, and the mediating function of RAR between them. Methods: A total of 1,961 subjects from the 2005 to 2018 National Health and Nutrition Examination Survey (NHANES) were included in this cross-sectional study. Weighted adjusted multivariate regression analyses were used to evaluate the association between OBS and DR risk. Weighted restricted cubic splines (RCS), mediation analysis and subgroup analysis were used to further elucidate these associations. Results: According to the multivariate logistic regression model, a significant negative association was found between OBS and DR risk after adjusting for all covariates (OR = 0.96, 95% CI: 0.94-0.99; P=0.007). When OBS were transformed into quartiles, participants in OBS quartile 4 (OR 0.42; 95% CI 0.22-0.80, P=0.009) presented a significantly lower risk of DR than did those in OBS quartile 2 and OBS quartile 3. The RCS results further revealed a nonlinear association between OBS and DR, after adjusting for all covariates (P for nonlinearity <0.01). The results of the subgroup analysis revealed that the association between OBS and DR remained stable over most subgroups (p for interaction >0.05), except for smoking status (p for interaction = 0.017). Conclusion: OBS is negatively associated with DR. There is a nonlinear relationship between OBS and DR, which may be mediated partly by RAR.