Association of blood glucose levels with ocular diseases in the middle-aged and elderly population: results from the NHANES 2005-2008

Background The aim of this study was to investigate the relationship between blood glucose levels and risk of ocular diseases, including diabetic retinopathy (DR), cataract, glaucoma, and age-related macular degeneration (AMD) in the middle-aged and elderly population. Methods The National Health and Nutrition Examination Survey (NHANES) data from 2005 to 2008 were used for this study. The correlation between blood glucose and risk of ocular disease was examined using weighted multivariate logistic regression analysis, restricted cubic spline curve (RCS) plots, and subgroup analysis. The XGBoost algorithm was further used to rank the importance of the influencing factors. Results In the unadjusted model, higher blood glucose levels were significantly associated with an increased risk of DR (OR = 8.189, 95% CI: 2.687–24.96, p  = 0.001), cataracts (OR = 2.134, 95% CI: 1.304–3.492, p  = 0.005), and glaucoma (OR = 2.734, 95% CI: 1.588–4.708, p  = 0.001). RCS analysis further revealed that the risk of DR and glaucoma increased when blood glucose levels exceeded 104.63 mg/dL, while the risk of cataracts began to increase significantly when blood glucose levels surpassed 163.92 mg/dL. The XGBoost algorithm indicated that blood glucose was a prominent predictor in the development of ocular diseases. Conclusions Higher blood glucose levels are associated with an increased risk of ocular diseases, suggesting that early glycemic control may be an effective measure for preventing the onset of ocular diseases in middle-aged and elderly populations.