. Author manuscript; available in PMC: 2012 Jul 1.

Published in final edited form as: Hepatology. 2011 Jul;54(1):173–184. doi: 10.1002/hep.24351

Table 1.

IBD as a Potential Risk factor for Cholangiocarcinoma

First author	Country	Study dates	Study design	Risk factor	CC Type	Cases (% with risk factor)	Controls (% with risk factor)	Risk estimate (95% CI)	Selected adjusted variables
Welzel⁴⁸	Denmark	1978–1991	Case-Control	IBD	ICC	764 (0.92%)	3,056 (0.20%)	4.67 (1.6–13.9)	Age, sex
Erichsen⁴⁹	Denmark	1978–2003	Cohort	UC	ECC/ICC	Incidence rate 8.2	Incidence rate 2.0	4.1 (2.4–6.8)	Age, sex
				Crohn’s	ECC/ICC	Incidence rate 4.3	Incidence rate 1.4	3.0 (0.9–8.6)
Shaib⁴⁷	US	1993–1999	Case-control	UC	ICC	625	90,834	2.2 (1.2–3.9)	Age, sex, race, geographic location
				Crohn’s	ICC			2.0 (0.6–6.3)
Welzel²⁸	US	1993–1999	Case-Control	UC	ICC	535 (2.4%)	102,782 (0.6%)	4.5 (2.6–7.9)	Age, sex, race, geographic location
				Crohn’s	ICC	535 (0.9%)	102,782 (0.4%)	2.4 (1.0–5.9)
				UC	ECC	549 (0.9%)	102,782 (0.6%)	1.7 (0.7–4.0)
				Crohn’s	ECC	549 (1.1%)	102,782 (0.4%)	2.8 (1.3–6.4)

IBD = inflammatory bowel disease; UC = ulcerative colitis; CC = cholangiocarcinoma; ICC = intrahepatic cholangiocarcinoma; ECC = extrahepatic cholangiocarcinoma; CI = confidence interval