Vitamin B12 Intake and Diabetic Kidney Disease: A NHANES-Based Cross-Sectional Study with Transcriptomic Identification of P2RY14.

Diabetic kidney disease (DKD) is a major diabetic complication, and the association between vitamin B12 intake and DKD remains unclear. This cross-sectional study included 8,218 participants from the National Health and Nutrition Examination Survey (NHANES) 2011-2018. Multivariable logistic regression showed that participants in the highest vitamin B12 intake quartile had lower odds of DKD than those in the lowest quartile (Odds ratio (OR): 0.70; 95% confidence interval (CI): 0.50-0.97). Restricted cubic spline analysis indicated a significant nonlinear association between vitamin B12 intake and DKD. Transcriptomic analysis identified 493 differentially expressed genes (DEGs), of which 20 overlapped with cobalamin-related genes. P2RY14 was significantly upregulated in DKD and showed preliminary discriminatory ability across GSE30528, GSE30529, and GSE142025. Functional enrichment analyses suggested associations between P2RY14 and extracellular matrix-receptor interaction, focal adhesion, and kidney development. Exploratory molecular docking predicted a potential binding mode between MC-1 and P2RY14, with a Vina score of -6.0 kcal/mol. Overall, these findings support an association between vitamin B12 intake and DKD and identify P2RY14 as a hypothesis-generating candidate for further investigation.