Table 1

Prevalence (%) of adenomatous polyps by decade of life

		n		Age group (years)
		n		<40	40–49	50–59	60–69	70+	Total
Autopsy studies2-4 1-150
Blatt⁵	446	0	21	34	34	44	39
Arminski and McLean⁶	1000	20	19	27	35	46	33
Stemmermann and Yatani⁷	202	43	–	72	59	63	62
Rickert and colleagues⁸	518	–	17	35	56	58	47
Vatn and Stalsberg⁹	445	–	6	23	31	46	33
Jass and colleagues10	303	3	11	33	30	36	24

Colonoscopy studies in screened populations
DiSario and colleagues11	119	–	–	21	45	53	41
Lieberman and Smith12	105	–	–	28	41	58	41
Rex and colleagues13	496	–	–	20	331-151	311-152	26

Weighted averages
Necropsy studies	2914	9	15	31	40	48	37
Screening studies	720	–	–	20	38	37	31
v
Acromegalics (Jenkins and colleagues¹)	129	8	12	29	36	39	26

↵1-150 Three other autopsy studies (Correa and colleagues²; Eide and colleagues³; Williams and colleagues⁴) were considered but not included as the age bands in these studies did not correspond with those used by Jenkinset al.1
↵1-151 Patients aged 60–64;
↵1-152 patients aged 65–75.