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

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.