Urinary Sodium-Potassium Ratio and Cataract Risk: Insights From the NHANES 2003-2006 and Mendelian Randomization...

This study was based on the National Health and Nutrition Examination Survey (NHANES) and Mendelian randomization (MR) to explore the link between cataract and urinary sodium-potassium ratio (Na/K) ratio.

This study included 3,482 subjects from the 2003 to 2006 survey, with 305 cataract patients and 3177 controls. Baseline characteristics were analyzed using weighted χ2 or t-tests. Three models and stratified analyses assessed the association between Na/K ratio and cataracts. Receiver operating characteristic (ROC) curves and a k-nearest neighbor (KNN) model were used to evaluate the predictive value of the Na/K ratio for cataracts. MR analysis was conducted to explore the causal relationship between Na/K ratio and cataracts.

The Na/K ratio was significantly higher in cataract patients (P < 0.001). Three models-Model 1 (P = 2.64 × 10-5, odds ratio [OR] = 0.860), Model 2 (P = 3.60 × 10-4, OR = 0.872), and Model 3 (P = 5.14 × 10-3, OR = 0.895)-and stratified analyses (P = 0.00514, OR = 0.900) showed a significant association with cataract. The ROC curve (area under the curve value = 0.790) and KNN model confirmed the strong predictive value of the Na/K ratio. MR analysis indicated a causal relationship with cataract, suggesting the Na/K ratio as a protective factor.

The present study demonstrated a remarkable causal relationship between Na/K ratio and cataract, offering a new direction for the diagnosis and treatment of cataract.

Using MR with NHANES, causal hypotheses from basic research can be validated in a broader population, advancing personalized treatment in clinical care.