Table 1. Bidirectional MR estimates for the association between chronic periodontitis and Alzheimer’s disease.

Method	Periodontitis on Alzheimer’s disease						Alzheimer’s disease† on periodontitis
	Instrumental SNPs* from Munz et al.			Instrumental SNPs# from Shungin et al.
	OR (95% CI)	P value	Q statistic/ P value	OR (95% CI)	P value	Q statistic/ P value	OR (95% CI)	P value	Q statistic/ P value
IVW	1.10 (1.02, 1.19)	0.02	2.76/0.60	0.97 (0.87, 1.08)	0.59	4.13/0.66	1.00 (0.96, 1.04)	0.85	21.46/0.31
Weighted median	1.08 (0.98, 1.20)	0.13		0.99 (0.86, 1.14)	0.89		0.98 (0.94, 1.03)	0.44
MR-Egger	0.97 (0.68, 1.39)	0.89	2.27/0.52	1.05 (0.86, 1.27)	0.66	3.28/0.66	0.98 (0.93, 1.03)	0.41	20.00/0.33
MR-RAPS	1.10 (1.01, 1.20)	0.02		0.97 (0.86, 1.09)	0.60		0.99 (0.95, 1.04)	0.81

CI: confidence interval; OR: odds ratio; IVW: inverse-variance weighted; MR: Mendelian randomization; RAPS: robust adjusted profile score; SNP: single-nucleotide polymorphism

*Five/seven^# SNPs were used as instrumental variables for periodontitis respectively

^†Twenty SNPs were used as instrumental variables for Alzheimer’s disease