Table 2 Case–control studies showing an association between H pylori and asthma, allergic rhinitis and atopic disease

Author, year (reference)	Location	Study population	Age (years)	H pylori measure	Definition of outcome	Major findings: Condition and OR (95% CI) in relation to H pylori+
Matricardi, 2000 (43)	Caserta, Italy	240 atopic cases and 240 non-atopic controls	17–24	IgG ELISA	Total IgE	Atopy:	0.76 (0.47 to 1.24)
					Atopy: logRU >1.2
					Non-atopic: logRU<0
Bodner, 2000 (55)	Grampion, Scotland	97 cases and 208 controls	39–45	IgG ELISA	Skin & specific IgE tests	Wheeze:	1.20 (0.70 to 2.20)
					Atopy: weal ⩾3 mm, or any IgE >0.35 IU/ml	Wheeze and asthma:	0.50 (0.20 to 1.50)
					Self-reported adult-onset wheeze and asthma	Atopy:	0.90 (0.60 to 1.60)
Tseng, 2000 (56)	Hong Kong	90 cases with stable asthma and 97 controls	Mean 43	IgG ELISA	Current asthma diagnosed by ATS guidelines	Asthma:	1.55 (0.83 to 2.90)
Jun, 2005 (57)	Japan	46 cases with asthma, and 48 healthy controls	Mean 52	IgG ELISA	Current asthma diagnosed by ATS guidelines	Compared with healthy controls, Asthma:	1.10 (0.45 to 2.69)
Jun, 2005 (57)	Japan	46 cases with asthma, and 48 healthy controls	Mean 52	IgG CagA		For CagA+, Asthma:	1.20 (0.39 to 3.69)