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 valuea | 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 studiesd | ||||
| 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.
a P 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.