Table I.

Selected baseline characteristics of colorectal cancer cases and matched controls: SMHS (2002–06)^a

Baseline characteristics	Cases (n = 288)	Controls (n = 576)	P
Age at sample collection (%)
<60 years	34.0	33.7
60–69 years	39.6	38.0
≥70 years	26.4	28.3	0.826
Education (%)
Primary school or below	12.5	14.1
Middle school	34.3	30.6
High school	23.7	29.6
College or above	29.5	25.7	0.209
Income (%)
<1000 yuan/month	52.3	55.6
1000–1999	38.4	37.2
≥2000	9.3	7.2	0.448
Occupation (%)
Professional	35.5	37.7
Clerical	20.1	17.0
Manual laborer	44.4	45.3	0.494
Currently married (%)	86.1	86.7	0.815
Smoking
Non-smoker	36.4	39.4
Former smoker or light smoker	33.5	36.3
Heavy smoker (≥10 cigarettes/day)	30.1	24.3	0.178
Regular alcohol consumption (%)	32.0	31.8	0.965
Regular exercise
No	51.2	46.2
METs <2.69	24.2	26.8
METs ≥2.69	24.6	27.0	0.352
BMI
<25	58.4	65.5
25–29.9	36.4	32.4
≥30	5.2	2.1	0.014
WHR
<0.88	26.5	33.2
≥0.88	24.3	30.6
≥0.92	49.3	36.2	0.001
Family history of cancer (%)	38.0	29.4	0.011
Number of selected diseasesb
0–1	50.8	63.4
2	26.0	22.9
≥3	23.2	13.7	<0.001

MET, metabolic equivalent.

^aAdjusted for age at sample collection.

^bIncludes diabetes, hypertension, cardiovascular diseases, prostatic hypertrophy, gastritis, gastrointestinal ulcer, bronchitis and polyps.