ObjectiveTo assess the diagnostic utility of lncRNA 51A in detecting cognitive decline among aluminum-exposed workers occupationally. Methods921 male workers from an aluminum manufacturing facility underwent cognitive assessments, measurement of plasma aluminum levels and quantification of lncRNA 51A levels. Receiver Operating Characteristic (ROC) curves were constructed to assess the diagnostic potential of lncRNA 51A. Bayesian network model was utilized to predict the likelihood of cognitive decline among the study population. ResultsSignificant differences in lncRNA 51A levels, plasma aluminum concentration and MMSE scores were observed between cognitive normal and decline groups. The lncRNA 51A expression was negatively correlated with MMSE scores. The area under the curve (AUC) was 0.894, with 89.3% sensitivity and 73.9% specificity. The Bayesian network model indicated varying probabilities of cognitive decline based on lncRNA 51A expression levels. ConclusionPlasma lncRNA 51A shows potential as an excellent biomarker for cognitive decline diagnosis in aluminum-exposed workers.