High education, low obesity, and reduced alcohol intake correlated with a lower risk of delirium

Objective: Identifying risk factors for delirium is crucial for informing public health strategies; however, establishing causal relationships from epidemiological data remains challenging. This study aims to determine whether educational attainment, obesity, and various lifestyle factors are causally associated with delirium. Methods: A univariate two-sample and multivariable Mendelian randomization (MR) approach was employed to evaluate the causal effects of educational attainment, obesity, and multiple lifestyle factors on the risk of delirium, followed by examining whether these associations were independent of one another. Results: MR analysis using the inverse-variance weighting method revealed significant associations between educational attainment (OR = 0.85; 95% CI: 0.77–0.93; p < 0.001), body mass index (BMI)(OR = 0.74; 95% CI: 0.57–0.97; p = 0.031), alcohol consumption (OR = 8.62; 95% CI: 2.74–27.12; p < 0.001), and smoking initiation (OR = 1.71; 95% CI: 1.17–2.50; p = 0.006) with delirium tremens. Multivariable MR confirmed independent causal effects of education (OR = 0.79), alcohol consumption (OR = 0.64), and BMI (OR = 5.51) on delirium tremens. Mediation analysis indicated that education influences risk indirectly through BMI, alcohol use, and smoking. No significant causal relationships were found for non-alcohol or psychoactive substance-induced delirium. Conclusions: Higher educational attainment, lower BMI, and reduced alcohol intake are causally linked to a lower risk of delirium tremens, while no such associations were found for non-alcohol or substance-induced delirium. These findings highlight the preventive potential of targeted education and lifestyle interventions.