Table 1.

Summary of the cumulative results of the main studies included.

Respiratory Disease		Result	Reference	Publication Year
	Meta-analysis of 18 studies	Negative association with H. pylori infection	[16]	2021
ASTHMA	Case-control study including 10,000 patients	Only in obese patients H. pylori associated with 30–40% OR of asthma ↓	[17]	2019
	Cohort study	16% of children uninfected at 2 and 10 years developed asthma at 16 years versus none of the children with H. pylori at 2 years	[19]	2020
CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD)	Case-control study including patients with type 2 diabetes mellitus and controls	In diabetics, seropositivity was significantly associated with chronic bronchitis	[31]	2020
	Retrospective cohort study (Taiwan)	Significant association between H. pylori and COPD	[32]	2017
	Case-control study (Korea, country with high burden of H. pylori)	No association between H. pylori and COPD	[33]	2016