Table 1.

Epidemiological data on HP infection and its association with AD

	Japan	China	USA	France	Sweden	Netherland	Greece	Turkey	Brazil	Ref
HP infection (%)	50–60	70–80	20–30	20–30	< 20	40–50	40–50	80–90	80–90	[69]
HP strain	East Asia	East Asia	Europe	Europe	Europe	Europe	Europe	Europe	Europe/Africa	[6]
AD and other dementias (%)	0.8–0.9	0.8–0.9	0.5–0.6	0.6–0.7	0.5–0.6	0.5–0.6	0.6–0.7	1.1–1.2	1–1.1	[65]
Risk ratio of HP infection to AD	0.94	0.66/1.39	1.45	2.85	1.21	1.06	2.76/8.4	ND	ND	[23]

Abbreviations: AD, Alzheimer’s disease; HP, Helicobacter pylori; ND, not determined