Risk factors for sporadic colorectal cancer in southern Chinese

Table 3 Stratification analysis of colon and rectal cancer

Variables	Adjusted OR (95% CI)1
	Test group		Validation group		Merged group
	Colon cancer (n = 253)	Rectal cancer (n = 260)	Colon cancer (n = 95)	Rectal cancer (n = 98)	Colon cancer (n = 348)	Rectal cancer (n = 358)
Smoking status
Non	1.00 (ref.)	1.00 (ref.)	1.00 (ref.)	1.00 (ref.)	1.00 (ref.)	1.00 (ref.)
Former	0.71 (0.34-1.49)	1.26 (0.59-2.69)	1.09 (0.44-2.72)	0.41 (0.14-1.18)	0.83 (0.48-1.43)	0.79 (0.45-1.38)
Current	1.34 (0.72-2.51)	1.87 (0.96-3.65)	1.03 (0.53-2.03)	0.78 (0.40-1.51)	1.22 (0.78-1.91)	1.17 (0.75-1.83)
Drinking status
Non	1.00 (ref.)	1.00 (ref.)	1.00 (ref.)	1.00 (ref.)	1.00 (ref.)	1.00 (ref.)
Former	2.28 (0.90-5.76)	1.32 (0.48-3.64)	2.51 (0.78-8.06)	3.10 (0.88-10.92)	2.51 (1.24-5.07)	1.71 (0.80-3.65)
Current	13.24 (7.78-22.51)	11.91 (7.14-19.87)	3.46 (1.83-6.53)	3.61 (1.94-6.74)	7.60 (5.13-11.25)	7.52 (5.13-11.01)
Family history of cancer
Negative	1.00 (ref.)	1.00 (ref.)	1.00 (ref.)	1.00 (ref.)	1.00 (ref.)	1.00 (ref.)
Positive	1.67 (1.01-2.75)	1.26 (0.76-2.09)	3.26 (1.12-9.45)	3.52 (1.26-9.85)	1.82 (1.17-2.82)	1.51 (0.97-2.35)
BMI (kg/m2)
≤ 23.9	1.00 (ref.)	1.00 (ref.)	1.00 (ref.)	1.00 (ref.)	1.00 (ref.)	1.00 (ref.)
≥ 24.0	1.48 (1.05-2.09)	1.22 (0.86-1.73)	1.18 (0.70-1.99)	2.00 (1.18-3.36)	1.38 (1.04-1.83)	1.35 (1.02-1.79)

¹Adjusted for age, sex, smoking status, alcohol drinking, family history of cancer, BMI.