. 2015 Mar;35(1):12–20. doi: 10.24095/hpcdp.35.1.03

TABLE 2. Distribution of colorectal cancer cases (n = 3171) and population-based controls (n = 3097) based on selected covariates, NECSS, Canada, 1994–1997.

	Cases		Controls		p value for Chi-Square
	n	%	n	%	p value for Chi-Square
Sex
Men	1816	57.2	1635	52.8
Women	1355	42.8	1462	47.2
Age, years
20–49	378	11.9	838	27.1	< .0001
50–59	645	20.4	605	19.5
60–69	1342	42.3	1043	33.7
≥ 70	806	25.4	611	19.7
Education, years
≤ 8	577	18.2	471	15.2	< .0001
9–13	1818	57.3	1689	54.5
≥ 14	711	22.4	900	29.1
Missing values	65	2.1	37	1.2
Family income^a
Low	584	18.4	584	18.9	0.32
Lower-middle	570	18.0	585	18.9
Upper-middle	758	23.9	779	25.2
High	474	14.9	440	14.2
Missing values	785	24.8	709	22.9
Pack-year smoking
Never smokers	995	31.4	1123	36.5	< .0001
≤ 10	626	19.7	705	23.0
11–20	525	16.6	470	15.3
21–30	377	11.9	302	9.8
> 30	592	18.7	447	14.5
Missing values	56	1.8	50	1.6
BMI, kg/m²
< 25.0	1175	37.1	1461	47.2	< .0001
25.0–29.9	1345	42.4	1176	38.0
≥ 30.0	637	20.1	447	14.4
Missing values	14	0.2	13	0.4
Moderate physical activity, hour/month
≤ 4.22	598	18.9	638	20.6	< .0019
4.23–11.57	645	20.3	702	22.7
11.58–24.44	720	22.7	725	23.4
≥ 24.45	730	23.0	636	20.5
Missing values	478	15.1	396	12.8
Strenuous physical activity, hour/month
Never	1324	41.8	1146	37.0	< .0006
≤ 0.19	174	5.5	162	5.2
0.20–3.68	565	17.8	644	20.8
≥ 3.69	597	18.8	647	20.9
Missing values	511	16.1	498	16.1
Calcium supplementation
Never	1944	61.3	1849	59.7	< .0001
Not regularly	603	19.0	649	20.9
Regularly	369	11.6	430	13.9
Missing values	255	8.0	169	5.5
Age at first pregnancy, years
≤ 20	270	19.9	358	24.5	< .01
21–23	343	25.3	343	23.5
24–26	238	17.6	239	16.4
> 26	302	22.3	283	19.4
Missing values	202	14.9	239	16.4

Abbreviations: BMI, body mass index; NECSS, National Enhanced Cancer Surveillance Study.

Family income was indicated as a categorical variable with the following values: low:< $20 000 with ≤ 3 people or $30 000 with ≥ 4 people; lower-middle: $20 000–$30 000 with ≤ 3 people or $30 000–$50 000 with ≥ 4 people; upper-middle: < $50 000 with ≤ 3 people or $50 000–$100 000 with ≥ 4 people; high: ≥ 50 000 for ≤ 3 people or ≥ 100 000 for ≥ 4 people.