Table 1

Characteristics of selected studies (n=32)

											Adjusted confounders
Study	Site	Data collection	Study design	Sample size	Male (%)	Age (years)	Median age (years)	Detection methods	Setting	Adjustments	Age	Sex	History of family	BMI	Smoking	Diet	Quality
Blanks et al 201539	UN	2006–2010	1	628976	0	60–69	65.2	TC, FS, CTC	1	Y	√	/		√	√		Low
Boutron-Ruault et al 200152	France	NA	2	1269	52.3	30–79	NA	TC	2	Y	√	√					Low
Botteri et al 201638	Italy	2007–2009	1	750	51.2	50–69	64	TC	2	Y	√	√			√	√	High
Brenner et al 201836	Canada	2008–2015	1	2496	53.8	50–74	NA	TC	2	Y	√	√	√	√	√		High
Burnett-Hartman et al 201353	USA	1998–2007	2	2506	NA	20–79	NA	TC	2	Y	√	√	√	√	√		High
Cao et al 201554	USA	1998–2008	1	22851	21.4	40–75	NA	Record	1	Y	√	/	√	√	√	√	High
Cao* et al 201572	USA	1998–2008	1	31065	100	40–75	NA	TC	1	Y	√	/	√	√	√	√	High
Carr et al 201755	Germany	2005–2014	1	15950	49.4	55–	63.3	TC	1	N							Low
Chia et al 200756	USA	1999–2003	2	348	42.8	30–79	NA	TC	3	N							Low
Enger et al 199735	USA	1991–1993	2	976	66.6	50–74	62	FS	2	Y				√	√	√	High
Frantz et al 201357	USA	2006–2008	1	934	49.6	30–80	55	TC	3	Y	√	√					High
Giovannucci et al 199558	USA	1986–1992	3	47723	100	40–75	NA	TC, FS	1	Y	√	/	√		√	√	High
Giovannucci et al 199659	USA	1986–1992	3	13057	0	40–65	NA	Record	1	Y	√	/	√		√	√	Low
Hauret et al 200460	USA	1995–1997	2	405	46.7	30–74	58.2#	TC	2	Y	√	√	√		√	√	High
Hermann et al 200961	Germany	1994–2007	3	25540	63.6#	35–65	NA	Record	1	Y	√	√	√	√	√	√	High
Jung et al 201540	Korea	2010–2011	1	28 504	80.9	30–59	NA	TC	3	Y		√	√	√	√		High
Karaginni et al 201062	Greec e	2008–2009	2	104	61.5	30–77	60#	TC	3	Y	√	√		√	√	√	High
Kato et al 199045	Japan	1986–1990	2	1324	64.9	NA	NA	TC	3	Y	√	√					High
Kim et al 201163	Korea	1998–2007	3	1562	69.7	20–	NA	FS	3	Y	√	√					Low
Knudsen et al 201664	Norway	2012–2013	1	14 832	48.5	50–74	62	FS	1	Y	√	√		√	√	√	Low
Kono et al 199965	Japan	1995–1996	1	803	100	47–55	NA	Record	2	Y		/			√		Low
Larsen et al 200666	Norway	1999–2002	1	6961	NA	50–64	NA	FS	1	Y	√	√		√	√	√	High
Liberman et al 200341	USA	1994–1997	1	3121	95.8	50–75	NA	TC	2	Y	√						High
Little et al 199367	France	1981–1988	2	476	NA	50–	NA	Record	2	Y	√	√					Low
Lubin et al 199768	Israel	NA	2	392	57	21–75	♂63♀60#	TC	3	Y						√	High
Massa et al 201469	USA	1991–2007	3	43641	0	42–62	NA	TC	1	N		/					High
Morimoto et al 200242	USA	1991–1994	2	1502	46.5	30–74	NA	TC	2	Y	√	/		√	√	√	High
Scnchez et al 2012	USA	2002–2010	1	982	41.8	45–	NA	TC	3	Y	√	√		√			High
Shinchi et al 199437	Japan	1991–1992	1	2228	100	49–55	NA	TC, FS	2	Y		/			√		Low
Song et al 201344	Korea	2008–2010	1	1526	57.2	21–78	49.2	TC	3	Y	√	√	√	√	√		High
Waldmann et al 201643	Austria	2008–2012	1	25 409	49.2	40–	60	TC	1	Y	√	/					High
Yang et al 201771	Korea	2003–2012	1	70 812	69.4	NA	41.6	TC	2	N							Low

Study design: 1, cross-sectional; 2, case-control; 3, cohort. Neoplasia related: 1, all adenoma; 2, advanced colorectal neoplasia; 3, non-advanced adenoma. Setting: 1, national screening programme/large cohort study; 2, multiple centres; 3, single hospital/site.
♂, male; /, not applicable due to homogenous study population; ♀, female; #, case group; CTC, CT colonography; FS, flexible sigmoidoscopy; N, no; TC, total colonoscopy; Y, yes.