Table 1.
Characteristics of the included studies on Helicobacter pylori infection and risk of lung cancer.
| First author, year | Country | Diagnosis | Study size | Number | QR | ||
|---|---|---|---|---|---|---|---|
| H. pylori infection | Lung cancer | Cases (H. pylori +) | Controls (H. pylori +) | ||||
| Gocyk, 2000 [14]# | Poland | A | A | 150 | 50 (45) | 100 (64) | 7 |
| Philippou, 2004 [17]# | Greece | A | A | 140 | 72 (44) | 68 (38) | 7 |
| Ece, 2005 [13]# | Turkey | A | A | 71 | 43 (40) | 28 (12) | 6 |
| Najafizadeh, 2007 [16]# | Iran | a | A | 80 | 34 (21) | 35 (18) | 8 |
| Kosunen, 2009 [15]∗ | Finland | a | NR | 26,705 | NA | NA | 7 |
| Behroozian, 2010 [12]# | Iran | a | A | 132 | 66 (48) | 66 (34) | 5 |
| Koshiol, 2012 [3]$ | Finland | a | B | 1,389 | 696 (550) | 693 (544) | 9 |
#Case-control study; ∗prospective study; $nested case-control study.
NR: not reported; NA: not applicable; QR: quality rating according to New castle-Ottawa Scale;
H. pylori +: number of patients with seropositivity of H. pylori.
a: Enzyme-Linked Immunosorbent Assay.
A: histologically conformed; B: registry based.