Table 3.

Direct effects of atrial fibrillation on brain volume phenotypes adjusted for genetic effects of ischemic stroke by multivariable MR analysis.

Genetically predicted exposure	Conditional F statistics (atrial fibrillation)	Conditional F statistics (stroke)	Outcome phenotype	Heterogeneity Q statistics P value	Method	Beta	Standard error	P value
Atrial fibrillation, adjusted for genetic effects of ischemic stroke (16 SNPs)	1.734	1.406	Gray matter volume (normalized)	0.443	IVW	−0.022	0.033	0.528
					MR-Egger	−0.001	0.065	0.992
			Gray matter volume (unnormalized)	0.397	IVW	−0.022	0.034	0.533
					MR-Egger	−0.015	0.066	0.823
			White matter volume (normalized)	0.035	IVW	0.014	0.045	0.758
					MR-Egger	−0.003	0.088	0.971
			White matter volume (unnormalized)	0.043	IVW	0.013	0.045	0.777
					MR-Egger	−0.005	0.087	0.958

MR Mendelian randomization, IVW inverse variance-weighted, SNP single-nucleotide polymorphism

Multivariable inverse variance-weighted method and MR-Egger regression was performed to yield the causal estimates