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

Table 1 Baseline characteristics and comparison of demographics between the cholecystectomy group and matched control group

Variables	Cholecystectomy, n = 174874	Control, n = 174874	P value
Age in years	55.67 ± 13.3	55.67 ± 13.3	1.00
Age group by year interval			1.00
20-39	20268 (11.59)	20268 (11.59)
40-64	106983 (61.18)	106983 (61.18)
≥ 65	47623 (27.23)	47623 (27.23)
Male sex	90271 (51.62)	90271 (51.62)	1.00
Income status for lower 25% group	33800 (19.33)	37275 (21.32)	< 0.0001
Smoking status			< 0.0001
Non-smoker	107630 (61.55)	108326 (61.95)
Ex-smoker, current cessation	34449 (19.70)	30501 (17.44)
Current smoker	32795 (18.75)	36047 (20.61)
Alcohol consumption			< 0.0001
None	108368 (61.97)	98356 (56.24)
Moderate as < 30 g/day	57373 (32.81)	64303 (36.77)
Heavy as ≥ 30 g/day	9133 (5.22)	12215 (6.99)
Regular physical activity	34582 (19.78)	35684 (20.41)	< 0.0001
BMI in kg/m2	24.71 ± 3.47	23.98 ± 3.26	< 0.0001
BMI group by kg/m2 interval			< 0.0001
< 18.5	3761 (2.15)	5273 (3.02)
18.5-23.0	50768 (29.03)	63622 (36.38)
23.0-25.0	43277 (24.75)	43801 (25.05)
25.0-30.0	64760 (37.03)	54738 (31.30)
≥ 30.0	12308 (7.04)	7440 (4.25)
Diabetes mellitus	29666 (16.96)	23076 (13.20)	< 0.0001
Hypertension	68635 (39.25)	61008 (34.89)	< 0.0001
Dyslipidemia	52115 (29.80)	48351 (27.65)	< 0.0001
Chronic kidney disease1	11414 (6.53)	9344 (5.34)	< 0.0001

¹Defined as estimated glomerular filtration rate of < 60 mL/minute/1.73 m².

Data are presented as n (%) or mean ± SD. BMI: Body mass index.