Relationship between alcohol use and traumatic brain injury: evidence from Mendelian randomization

Observational studies suggest that alcohol consumption increases the risk of traumatic brain injury (TBI); however, the causality of this association remains unclear. This study aimed to identify which drinking pattern is the primary factor influencing TBI. Two-sample Mendelian randomization (MR) was used to assess whether drinking patterns (alcohol consumption, abuse, and intake frequency) are causally associated with TBI risk. MR analysis revealed causal effects of alcohol intake frequency [odds ratio (OR) 0.806, 95% confidence interval (CI): 0.665-0.978, p = 0.028, beta: -0.215, se: 0.098], alcohol drinks per week (OR 1.772, 95% CI: 1.140-2.753, p = 0.011, beta: 0.572, se: 0.225), and alcohol abuse (OR 1.095, 95% CI: 1.006-1.192, p = 0.035, beta: 0.091, se: 0.043) on TBI. Additionally, no causal effect of alcohol consumption (OR 0.730, 95% CI: 0.264-2.025, p = 0.546, beta: -0.314, se: 0.520) or average monthly alcohol intake (OR 1.138, 95% CI: 0.805-1.609, p = 0.463, beta: 0.130, se: 0.177) on TBI was observed. Similarly, the effects of TBI on alcohol intake were statistically non-significant. Drinking patterns, including alcohol intake frequency and abuse, influence TBI, whereas TBI rarely influences drinking patterns.