Circulating concentrations of nutrition-related factors are not causally associated with atrial fibrillation: a Mendelian randomization study.

Observational studies reported conflicting results regarding the association between circulating concentrations of nutrition-related factors and atrial fibrillation (AF). The aim of this study was to evaluate the potential causal effect of eight circulating nutrition-related factors (vitamin B12, vitamin E, folate, retinol, β-carotene, iron, zinc, and copper) on AF risk using mendelian randomisation (MR). Summary-level data for the nutrition-related factors and AF were obtained from genome-wide association studies conducted among individuals of European ancestry. The genome-wide association study on AF included 60620 cases and 970216 controls. A two-sample MR design was applied for evaluating the causal association. In the primary MR analyses, the inverse-variance weighted method did not identify any causal effect of circulating concentrations of vitamin B12 (β=0.000, standard error (SE)=0.021, P=0.994), vitamin E (β=0.080, SE=0.152, P=0.600), retinol (β=0.098, SE=0.397, P=0.806), folate (β=-0.006, SE=0.052, P=0.901), β-carotene (β=0.014, SE=0.025, P=0.560), iron (β=-0.009, SE=0.072, P=0.905), zinc (β=0.038, SE=0.032, P=0.239), and copper (β=-0.012, SE=0.023, P=0.589) on AF. The MR-Egger and MR pleiotropy residual sum and outlier (MR-PRESSO) analyses did not suggest the presence of pleiotropy. In addition, the lack of association remained in the leave-one-out analysis. This MR study indicates no causal association of circulating concentrations of vitamin B12, vitamin E, folate, retinol, β-carotene, iron, zinc, and copper with AF.