Table 1.

Characteristics of the studies included in meta-analysis.

Author	Year	Country	Design	H. pylori Diagnostic Method	IBS Diagnostic Criteria	Sample Size (Total No. of Study Participants)	No. of IBS	No. of Control	No. of H. pylori (+) in IBS Group	No. of H. pylori (+) in Control Group	Male (%)	Mean Age ± SD or Median Age (Range)	Quality Assessment (Newcastle-Ottawa Scale)
Agreus L [27]	1995	Sweden	Case-control	ELISA (Antibody-IgG for H. pylori)	Diagnostic criteria developed by authors	150	50	50	16	23	36	48 (22–80)	S2, C0, E2
Antonio M [28]	1999	Spain	Case-control	Antibody-IgG for H. pylori	Rome criteria	100	50	50	27	29	50	34.1 ± 7.4 in IBS, 35.6 ± 5.6 in control	S2, C1, E2
G. Richard Locke III [19]	2000	USA	Cross-sectional	ELISA (Antibody-IgG for H. pylori)	Manning et al.	148	35	77	9	11	42	31 (20–50)	S3, C2, O3
Maura Corsetti [29]	2004	Belgium	Cross-sectional	Endoscopic biopsy and stain	Rome Ⅱ	309	144	165	14	21	33	42.0 ± 0.8	S2, C0, O3
Y. Zhao [21]	2010	China	Cross-sectional	ELISA (Antibody-IgG for H. pylori)	Rome Ⅱ	3148	147	3001	106	2204	47.8	42.5 ± 15.2	S4, C2, O3
J. Yakoob [16]	2012	Pakistan	Case-control	Endoscopic biopsy	Rome Ⅲ	330	170	160	91	71	69 in IBS, 66 in control	40 ± 15 in IBS, 42 ± 14 in control	S2, C0, O3
Su Youn Nam [22]	2013	Korea	Cross-sectional	Endoscopic biopsy, UBT	Rome Ⅲ	2769	258	2511	106	1224	65.5 in IBS, 60.3 in control	45.3 ± 8.6 in IBS, 50.2 ± 9.9 in control	S3, C2, O3
Al-Damarchi, A.T [30]	2018	Iraq	Case-control	H. pylori stool antigen test	Rome Ⅳ	135	60	75	21	23	22 in IBS, 42 in control	33.5 ± 2.5 in IBS, 34.8 ± 3.1 in control	S2, C1, E1
Aziza I Salem [31]	2019	Egypt	Case-control	H. pylori Ag ELISA	Rome III	120	40	40	10	12	NA	28 ± 9.5 in IBS, 33.5 ± 13.9 in control	S2, C2, E2
Odhar, H.A. [32]	2019	Iraq	Case-control	Antibody-IgG for H. pylori	Rome Ⅳ	60	30	30	17	12	20 in IBS, 53.3 in control	23 (19–50) in IBS, 23 (19–55) in control	S2, C1, E1

Abbreviations: SD, standard deviation; S, selection; C, comparability; E, exposure; O, outcome; NA, not available.