Table 2.

Risk factors for inadequate baseline flexible sigmoidoscopy ^a

Characteristics	All subjects N	Adequate examination n	Inadequate examination n	Proportion with inadequate examination (95% CI)	OR (95% CI)
Age group in years
55–59	21696	19497	2199	0.10 (0.10, 0.11)	1.0 (reference)
60–64	20015	17963	2052	0.10 (0.10, 0.11)	1.08 (1.01, 1.15)
65–69	14506	12806	1700	0.12 (0.11, 0.12)	1.27 (1.19, 1.36)
70–74	8337	7204	1133	0.14 (0.13, 0.14)	1.51 (1.39, 1.63)
Male	32992	30699	2293	0.07 (0.07, 0.07)	1.0 (reference)
Female	31562	26771	4791	0.15 (0.15, 0.16)	2.40 (2.27, 2.54)
Highest education attained
High School or Less	27057	23861	3196	0.12 (0.11, 0.12)	1.0 (reference)
Some/Graduated College	25265	22546	2719	0.11 (0.10, 0.11)	0.94 (0.89, 0.99)
Postgraduate	12158	10996	1162	0.10 (0.10, 0.10)	0.91 (0.84, 0.98)
Smoking status
Never	30187	26760	3427	0.11 (0.11, 0.12)	1.0 (reference)
Former	27854	24987	2867	0.10 (0.10, 0.11)	1.06 (1.00, 1.12)
Current	6494	5708	786	0.12 (0.11, 0.13)	1.16 (1.07, 1.27)
White, non-Hispanic	57616	51090	6526	0.11 (0.11, 0.12)	1.0 (reference)
Black, non-Hispanic	3020	2672	348	0.12 (0.10, 0.13)	0.89 (0.79, 1.00)
Hispanic	1120	996	124	0.11 (0.10, 0.13)	1.15 (0.95, 1.40)
Asian	2309	2255	54	0.02 (0.02, 0.03)	0.69 (0.50, 0.93)
American Indians/Pacific Islanders	463	434	29	0.06 (0.04, 0.09)	1.29 (0.87, 1.93)
Body mass index, kg/m2
≤25	21199	18373	2826	0.13 (0.13, 0.14)	1.0 (reference)
25–29	27287	24514	2773	0.10 (0.10, 0.11)	0.83 (0.78, 0.88)
≥30	15449	14030	1419	0.10 (0.09, 0.10)	0.67 (0.62, 0.72)

^aModel included all the variables in the table and screening center