Effect of smoking on the risk of gastrointestinal cancer after cholecystectomy: A national population-based cohort study

Table 2 Incidence rate and hazard ratio for the risk of colorectal cancer and gastric cancer after cholecystectomy

Cancer	Cholecystectomy	No.	Event	Duration1	IR2	HR (95%CI)
						Model 1	P value	Model 2	P value	Model 3	P value
CRC	No (control)	174874	1018	736081	1.38	1 (Ref.)	0.0005	1 (Ref.)	0.0004	1 (Ref.)	0.0013
	Yes	174874	1152	718563	1.60	1.16 (1.07-1.26)		1.16 (1.07-1.27)		1.15 (1.06-1.25)
GC	No (control)	174874	881	736344	1.20	1 (Ref.)	0.017	1 (Ref.)	0.015	1 (Ref.)	0.027
	Yes	174874	960	718935	1.34	1.12 (1.02-1.23)		1.12 (1.02-1.23)		1.11 (1.01-1.22)

¹Person-years.

²Per 1000 person-years.

Model 1 was not adjusted; Model 2 was adjusted for age and sex; Model 3 was adjusted for age, sex, smoking status, alcohol consumption, regular physical activity, hypertension, diabetes mellitus, dyslipidemia, body mass index, and estimated glomerular filtration rate. CRC: Colorectal cancer; GC: Gastric cancer; HR: Hazard ratio; IR: Incidence rate.