Effects of Helicobacter pylori infection in gastrointestinal tract malignant diseases: From the oral cavity to rectum

Table 1 Association with Helicobacter pylori infection and oral squamous cell carcinoma

	Prevalence of H. pylori	Diagnostic tool of H. pylori	Study design	P value
Fernando et al[13]	Betel Chewers (20/104; 19.2%) and non-betel chewers (4/69; 5.8%)	Serology	Case- control study	< 0.05
Grandis et al[14]	Case 57% vs controls 62%	Serology	Case- control study	> 0.05
Dayama et al [15]	OR: 3.0; 95%CI: 0.34-26.4	Serum and tissue samples (PCR and culture)	Case- control study	NA
Gupta et al[16]	OR: 2.29; 95%CI: 0.61-8.68	Serology, PCR, culture	Meta-analysis	NA
Meng et al[17]	Case 35.3% vs controls 54.8%	Serology, PCR, histochemical staining	Case- control study	0.012

H. pylori: Helicobacter pylori; OR: Odds ratio; CI: Confidence interval; PCR: Polymerase chain reaction; NA: Not available.