Table 1. The characteristics of the study population.

Variables	Cases (n=368)	Controls (n=500)	P value
Age
	52.8±5.5	52.9±5.6	0.791
Gender
Male	213	285	0.795
Female	155	215
Smoking status
Smokers	125	141	0.068
Non-smokers	243	359
Alcohol status
Drinkers	139	179	0.551
Non-drinkers	229	321
Body mass index
	24.2±2.5	23.1±2.4	P<0.001
Waist-hip-ratio
	0.82±0.004	0.81±0.005	P<0.001
Tumor site
Colon	207
Rectum	161
TNM stage
I	60
II	114
III	167
IV	27