Table 1. the main characteristics of included studies in this meta-analysis.

Study	Country	Design	Period	Population	Cancer type	Outcomes	NOS	LoE
Hemminki et al. 2009	Sweden	Cohort	1964–2004	21,788 CD	BCa, PCa and MGCa	SIR	9	2b
Jung et al. 2017	Korea	Cohort	2011–2014	5,825 UC and 3,918 CD	BCa and PCa	SIR	8	2b
Jussila et al. 2013	Finland	Cohort	2000–2010	16,649 UC and 5,315 CD	BCa and PCa	SIR	7	2b
Kappelman et al. 2014	Denmark	Cohort	1978–2010	13,756 CD and 35,152 UC	BCa and PCa	SIR	9	2b
Loo et al. 2019	Canada	Cohort	1998–2015	20,644 CD, 14,000 UC and 1,341 unspecified	PCa	SIR	9	2b
Ekbom et al. 1991	Sweden	Cohort	1965–1983	1,655 CD and 3,121 UC	BCa, PCa and MGCa	SIR	7	2b
Hemminki et al. 2008	Sweden	Cohort	1964–2004	27,606 UC	BCa, PCa and MGCa	SIR	9	2b
Jess et al. 2013	Denmark	Cohort	1978–2010	1,515 UC and 810 CD	MGCa and PCa	SIR	8	2b
So et al. 2017	China	Cohort	1990–2016	1,603 UC and 1,018 CD	PCa	SIR	7	2b
Karlén et al. 1999	Sweden	Cohort	1955–1989	1,547 UC	BCa, PCa and MGCa	SIR	8	2b
Bourrier et al. 2016	France	Cohort	2004–2005	11,759 CD and 7,727 UC	BCa	SIR	9	2b
Persson et al. 1994	Sweden	Cohort	1955–1989	1,251 CD	BCa and MGCa	SIR	7	2b
Mosher et al. 2018	USA	Case-control	1996–2015	2,080 IBD and 271,898 IBD-free	BCa and PCa	RR	7	3b
Wilson et al. 2016	UK	Case-control	1995–2012	19,647 IBD and 19,647 IBD-free	PCa	HR	8	3b
Burns et al. 2019	USA	Case-control	1996–2017	1,033 IBD and 9,306 IBD-free	PCa	HR	9	3b
Bernstein et al. 2001	Canada	Case-control	1984–1997	6,027 IBD and 5,529 IBD-free	BCa	IRR	9	3b

CD, Crohn’s disease; UC, ulcerative colitis; IBD, inflammatory bowel disease; BCa, bladder cancer; PCa, prostate cancer; MGCa, male genital cancer; SIR, standardized incidence ratio; RR, relative risk; HR, hazard ratio; IRR, incidence rate ratio; NOS, Newcastle-Ottawa Scale; LoE, level of evidence.