Helicobacter pylori and colorectal neoplasia: Is there a causal link?

Table 1 Overview of case-control studies evaluating the odds of colorectal neoplasia development with respect to Helicobacter pylori infection

Ref.	Cases/controls, n	Matching variables	Measure of H. pylori status	Outcome	Adjusted OR (95%CI)
Talley et al[20], 1991, United States	80/252	Convenience sample	IgG	Cancer	1.17 (1.03-2.84)
Penman et al[26], 1994, United Kingdom	42/34	Age, Gender	UBT	Cancer	1.31 (0.52-3.26)
Moss et al[25], 1995, United States	41/41	Age, Gender, Race	IgG	Cancer	0.74 (0.30-1.79)
Meucci et al[18], 1997, Italy	94/100	Age, Gender	IgG	Adenoma or Cancer	1.92 (1.08-3.43)
Thorburn[29], 1998, United States2	233/233	Age, Gender, Education, Region, Date	IgG	Cancer	1.02 (0.69-1.51)
Breuer-Katschinski et al[14], 1999, Germany	98/98	Age, Gender	IgG	Polyp	2.10 (1.12-3.92)
Fireman et al[21], 2000, Israel	51/51	Convenience sample	IgG	Cancer	2.43 (1.00-5.59)
Hartwich et al[16], 2001, Poland	80/160	Age, Gender	IgG, UBT	Cancer	3.78 (1.89-7.53)
Shmuely et al[27], 2001, Israel	67/92	Convenience sample	IgG, CagA	Cancer	1.35 (0.67-2.74)
Siddheshwar et al[28], 2001, United Kingdom	189/179	Age, Gender, Social class	IgG	Cancer	1.1 (0.7-1.8)
				Polyp	1.3 (0.7-2.5)
Limburg et al[23], 2002, Finland2	118/236	Age, Gender1, Study center, Date of serum collection	CagA, whole cell assay	Cancer	0.91 (0.53-1.55)
Fujimori et al[15], 2005, Japan	481/188	Age	UBT, urease test, histological diagnosis	Adenoma	1.60 (1.18-2.02)
				Cancer	1.80 (1.28-2.32)
Inoue et al[17], 2011, Japan3	239/239	Age	IgG	Adenoma	2.52 (1.57-4.05)
Zhang et al[30], 2012, Germany3	1712/1669	Age, Gender, Colorectal risk factors, Former colorectal endoscopy	IgG, CagA	Cancer	1.22 (1.02-1.45)

¹Only male smokers were included in the study;

²Nested case-control study;

³Population-based case-control studies. Data refer to studies reporting ORs or information from which such measure could be inferred. IgG: Immunoglobulin G; UBT: Urea breath test; CagA: Cytotoxin-associated gene A; H. pylori: Helicobacter pylori.

Table 2 Published meta-analyses evaluating the relationship between Helicobacter pylori infection and the development of colorectal neoplasia

Ref.	Included studies, n	Outcome	Summary OR (95%CI)	Conclusion
Zumkeller et al[45], 2006, Germany	111	Cancer	1.4 (1.1-1.8)	Possible small increase in the risk of CRC
Zhao et al[44], 2008, China	131 (9 using IgG to detect infection status)	Cancer	1.49 (1.17-1.91)	Possible increase in risk of CRC
			1.56 (1.14-2.14) evaluating IgG as the only test indicator)
Hong et al[34], 2012, South Korea	10	Adenoma	1.58 (1.32-1.88)	Modest increase in the risk of colorectal adenoma
Wu et al[43], 2013, China	27	Adenoma	1.66 (1.39-1.97)	Positive association between H. pylori and colorectal neoplasia
		Cancer	1.39 (1.18-1.64)
Rokkas et al[42], 2013, Greece	28	Polyps	1.50 (1.26-1.79)	Modest statistically significant relationship of H. pylori with both cancer and polyps
		Cancer	1.30 (1.07-1.59)
Chen et al[46], 2013, China	22	Cancer	1.49 (1.30-1.72)	H. pylori increases the risk of CRC
Guo et al[41], 2014, China	92	Hyperplastic polyp	0.72 (0.44-1.18)	No statistical association between H. pylori and colorectal neoplasm was found, but H. pylori may increase the risk of adenoma
		Adenoma	1.83 (1.35-2.51)
		Cancer	1.08 (0.89-1.68)

¹Only case-control studies were included;

²Included only data based on East-Asian population. H. pylori: Helicobacter pylori; IgG: Immunoglobulin G; CRC: Colorectal cancer.