Table 2.

Association between receipt of screening endoscopy and colorectal adenocarcinoma death risk

Screening colonoscopy status according to colon location			Estimated relative risks (95% CI)
	Case patients, n=1747	Matched control patients, n=3460	Bivariate model	Multivariate model*
All locations in the colon/rectum
No screening endoscopy	1358	2310	1.00	1.00
Screening colonoscopy	24	120	0.33 (0.21 to 0.52)	0.33 (0.21 to 0.52)
Screening sigmoidoscopy	365	1030	0.60 (0.52 to 0.69)	0.64 (0.56 to 0.75)
Right colon
No screening endoscopy	649	1151	1.00	1.00
Screening colonoscopy	13	61	0.37 (0.20 to 0.68)	0.35 (0.18 to 0.65)
Screening sigmoidoscopy	218	535	0.72 (0.59 to 0.87)	0.75 (0.62 to 0.92)
Left colon/rectum
No screening endoscopy	669	1092	1.00	1.00
Screening colonoscopy	9	56	0.25 (0.12 to 0.50)	0.25 (0.12 to 0.53)
Screening sigmoidoscopy	138	468	0.48 (0.38 to 0.59)	0.52 (0.41 to 0.66)

*The multivariate model adjusted for race/ethnicity, family history, percentage of people 25+ years in the census tract with at least a high-school diploma, Charlson comorbidity score and number of primary care visits, as well as an indicator faecal occult blood testing. The estimates were obtained from conditional regression models.