In a Mendelian randomized study (approximating thepossibility of causal inference) by Yang et al. [52] including 8964subjects, the rs671 polymorphism of the ALDH2 gene (decreased activityresulting in greater accumulation of the highly toxic acetaldehyde) showed asignificant association with the risk of AF in men (OR = 1.65; 95% CI:1.06–2.67). Here, ALDH2 is linked to atrial fibrillation.