Hepatitis B or C viral infection and risk of pancreatic cancer: A meta-analysis of observational studies

Table 2 Characteristics of studies included in the meta-analysis

Ref.	Population	Study design	Country	Ethnicity	Case (n)	No. of control	Confirmation of HBV/HCV	Confirmation of PC	Matching criteria
Berrington de Gonalez et al[9]	Population-based	Cohort	South Korea	Asian	2194	628978	HBsAg	clinic diagnosed	Age, sex
Hong et al[10]	Hospital-based	CC	South Korea	Asian	506	1008	Anti-HCV, Anti-HBs, HBsAg	histologically confirmed	Age, sex
Hassan et al[11]	Hospital-based	CC	United States	White	476	879	Anti-HCV,Anti-HBs, Anti-HBc	pathologically confirmed	Age, sex, race
El-Serag et al[3]	Population-based	Cohort	United States	Asian	140	477	Anti-HCV, HBV	ICD-9	Age, sex
Iloeje et al[2]	Population-based	Cohort	Taiwan	Asian	48	22471	HBsAg, HBV DNA	pathologically confirmed	Age, sex, smoking, alcohol
Wang et al[18]	Hospital-based	CC	China	Asian	645	711	HBsAg, Anti-HBs, Anti-HBc	pathologically confirmed	Age, sex
Zhu et al[17]	Hospital-based	CC	China	Asian	80	77	HBsAg, Anti-HCV, Anti-HBc	pathologically confirmed	Age, sex
Ben et al[12]	Hospital-based	CC	China	Asian	943	1128	HBsAg, Anti-HBs, Anti-HBc	pathologically confirmed	Age, sex, smoking, DM, BMI

CC: Case-control study; HBV: Hepatitis B virus; HCV: Hepatitis C virus; HBsAg: Hepatitis B surface antigen; Anti-HBs: Anti-hepatitis B surface antigen; Anti-HBc: Anti-hepatitis B core antigen; Anti-HCV: Anti-hepatitis C virus; ICD-9: International Classification of Diseases, Ninth Revision; DM: Diabetes mellitus; BMI: Body mass index.