Table 1.

Causal estimates of atrial fibrillation on brain gray or white matter volume in the UK Biobank participants by summary-level Mendelian randomization

Genetically predicted exposure	Outcome phenotype	MR-Egger intercept P value	Cochran’s Q statistic P value for heterogeneity	MR method	Beta	Standard error	P value
Atrial fibrillation (16 SNPs)	Gray matter volume (normalized)	0.984	0.547	IVW	−0.040	0.017	0.017
				MR-Egger (bootstrap)	−0.044	0.040	0.147
				Weighted median	−0.047	0.023	0.044
				MR-RAPS	−0.043	0.017	0.014
				MR-PRESSO	NA	NA	NA
	Gray matter volume (unnormalized)	0.817	0.499	IVW	−0.041	0.017	0.015
				MR-Egger (bootstrap)	−0.052	0.040	0.089
				Weighted median	−0.050	0.023	0.033
				MR-RAPS	−0.044	0.017	0.013
				MR-PRESSO	NA	NA	NA
	White matter volume (normalized)	0.549	0.041	IVW	−0.016	0.022	0.465
				MR-Egger (bootstrap)	−0.038	0.042	0.186
				Weighted median	−0.027	0.023	0.242
				MR-RAPS	−0.015	0.022	0.483
				MR-PRESSO	NA	NA	NA
	White matter volume (unnormalized)	0.553	0.053	IVW	−0.016	0.022	0.464
				MR-Egger (bootstrap)	−0.038	0.041	0.181
				Weighted median	−0.028	0.024	0.241
				MR-RAPS	−0.016	0.022	0.470
				MR-PRESSO	NA	NA	NA

MR Mendelian randomization, IVW inverse variance–weighted, RAPS robust adjusted profile score, PRESSO pleiotropy residual sum and outlier, SNP single-nucleotide polymorphism

MR-PRESSO analysis was performed, but the MR-PRESSO global test for heterogeneity did not identify correctable effects of outliers

The units of the causal estimates were log odds ratio for the cause (atrial fibrillation) and standard deviation for the effect (brain volume)