Helicobacter pylori Infection and Risk of Lung Cancer: A Meta-Analysis

Table 2

Overall effect estimates for Helicobacter pylori infection and lung cancer according to study characteristics.

Study	No. of studies	Random-effects model:	Heterogeneity between studies
		Overall OR (95% CI)	𝑃 value^a	𝐼^2 value
All	7	2.29 (1.34–3.91)	<0.01	83.9%
Sensitivity analysis
All except study by Ece et al. [13]^b	6	1.88 (1.14–3.18)	<0.01	80.9%
Study design
Cohort	1	2.63 (1.95–3.55)	NA	NA
Case-control	6	2.28 (1.19–4.39)	<0.01	79.9%
Time of Zhuo et al. [18]^c
Published in time frame covered in Zhuo et al. [18]	4	3.11 (1.07–9.04)	<0.01	80.9%
Published after Zhuo et al. [18]	3	1.87 (0.93–3.37)	<0.01	90.1%
Histology of lung cancer
Lung adenocarcinoma	1	1.1 (0.75–1.6)	NA	NA
Lung squamous cell carcinoma	1	1.1 (0.77–1.7)	NA	NA
Quality of included studies^d
High quality	1	1.09 (0.85–1.41)	NA	NA
Medium quality	4	2.12 (1.24–3.61)	0.05	61.1%
Low quality	2	6.12 (0.90–41.38)	0.01	82.6%

OR: Odds ratio; CI: confidence interval; NA: not available.
^a𝑃 value obtained by Cochrane 𝑄 test.
^bEce et al. [13] is the one of the included studies which has wider confidence interval.
^cZhuo et al. [18] is the recent meta-analysis done on this subject.
^dQuality of-included studies was assessed using Newcastle-Ottawa Scale.