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

Table 3 Incidence rate and hazard ratio for the risk of colorectal cancer and gastric cancer after cholecystectomy according to smoking habits

Parameter		Colorectal cancer				Gastric cancer
		IR1	HR (95%CI)			IR1	HR (95%CI)
			Model 1	Model 2	Model 3		Model 1	Model 2	Model 3
Smoking status	Non-smoker	1.46	1 (Ref.)	1 (Ref.)	1 (Ref.)	1.04	1 (Ref.)	1 (Ref.)	1 (Ref.)
	Ex-smoker	2.15	1.48 (1.29-1.70)	1.33 (1.12-1.57)	1.35 (1.14-1.60)	2.10	2.01 (1.74-2.34)	1.15 (0.97-1.36)	1.19 (1.00-1.40)
	Current smoker	1.52	1.04 (0.89-1.22)	1.38 (1.15-1.66)	1.40 (1.16-1.69)	1.51	1.45 (1.23-1.71)	1.33 (1.10-1.60)	1.35 (1.12-1.64)
	P value		< 0.0001	0.0005	0.0002		< 0.0001	0.0110	0.0064
Smoking quantity	Non-smoker	1.46	1 (Ref.)	1 (Ref.)	1 (Ref.)	1.04	1 (Ref.)	1 (Ref.)	1 (Ref.)
	0 < pack-years < 10	1.30	0.89 (0.73-1.09)	1.2 (0.98-1.53)	1.26 (1.01-1.57)	1.11	1.06 (0.85-1.32)	1.03 (0.81-1.30)	1.06 (0.84-1.35)
	10 ≤ pack-years < 20	1.41	0.97 (0.79-1.19)	1.16 (0.92-1.46)	1.19 (0.94-1.50)	1.33	1.27 (1.03-1.58)	1.01 (0.80-1.28)	1.05 (0.83-1.33)
	20 ≤ pack-years < 30	1.96	1.35 (1.09-1.66)	1.39 (1.10-1.75)	1.41 (1.12-1.78)	2.10	2.01 (1.63-2.48)	1.33 (1.06-1.70)	1.37 (1.09-1.72)
	30 ≤ pack-years	3.03	2.08 (1.77-2.45)	1.59 (1.31-1.92)	1.59 (1.31-1.93)	3.14	3.00 (2.53-3.55)	1.42 (1.18-1.71)	1.43 (1.19-1.73)
	P value		< 0.0001	< 0.0001	< 0.0001		< 0.0001	0.0010	0.0010

¹Per 1000 person-years.

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