Table 2.

Association between use of antibiotics and risk of colorectal polyps

	Nonusers		Users		OR (95% CI)		P value†
	No. of cases	No. of sibling controls	No. of cases	No. of sibling controls	Model 1*	Model 2†
All antibiotics	16,860	40,085	28,884	53,222	1.31 (1.26–1.36)	1.08 (1.04–1.13)	0.0003
Narrow-spectrum antibiotics	22,279	49,854	23,465	43,453	1.23 (1.18–1.27)	1.05 (1.01–1.10)	0.01
Broad-spectrum antibiotics	26,650	61,519	19,094	31,788	1.40 (1.35–1.46)	1.23 (1.18–1.29)	<0.0001
Anti-aerobic antibiotics	17,307	41,040	28,437	52,267	1.30 (1.25–1.35)	1.08 (1.04–1.13)	0.0003
Anti-anaerobic antibiotics	41,414	85,925	4,330	7,382	1.23 (1.16–1.31)	1.10 (1.03–1.18)	0.006
Penicillin	23,330	51,888	22,414	41,419	1.21 (1.17–1.26)	1.04 (1.00–1.09)	0.04
Tetracyclines	34,074	74,729	11,670	18,578	1.36 (1.30–1.42)	1.21 (1.16–1.27)	<0.0001
Quinolones	39,043	82,635	6,701	10,672	1.36 (1.29–1.44)	1.21 (1.14–1.28)	<0.0001
Macrolides	40,482	84,607	5,262	8,700	1.28 (1.21–1.36)	1.14 (1.08–1.22)	<0.0001
Sulfonamides and trimethoprim	41,890	87,029	3,854	6,278	1.26 (1.18–1.35)	1.16 (1.08–1.24)	<0.0001
Cephalosporins and other non-penicillin beta-lactams	43,064	88,721	2,680	4,586	1.24 (1.15–1.34)	1.13 (1.04–1.23)	0.005
Other classes	42,785	88,183	2,959	5,124	1.15 (1.06–1.24)	1.07 (0.99–1.16)	0.10

^*Conditional logistic regression was used with adjustment for age (continuous), sex (binary), and year of birth (continuous).

^†Multivariable model was further adjusted for income levels (quintiles), education (9 years or less, 10–12 years, >12 years, missing), total number of prior clinic visits (quintiles), Charlson comorbidity score (continuous), and major comorbidities (all binary, including diabetes, cardiovascular disease, non-colorectal cancer, liver disease, chronic pulmonary disease, connective tissue disease, and peptic ulcer disease).