Table 1 Baseline characteristics of breast cancer cases and controls in relation to menopausal status.
Premenopausal women Postmenopausal women
Variables Cases
(n=310)
%		 Controls
(n=475)
%		 Cases
(n=548)
%		 Controls
(n=610)
%
Age in reference year (yrs) ≤49
50-64
≥65		 75.5
24.5
0		 72.5
27.5
0		 8.0
50.5
41.6		 6.9
53.0
40.1
Current BMI (kg/m2) ≤22.5
22.6-<25.0
25-<30
≥30		 33.2
27.1
29.0
10.6		 31.2
27.2
32.4
9.3		 14.2
23.2
40.3
22.3		 25.7
22.6
35.7
15.9
Age at menarche ≤12
13
≥14		 19.3
27.7
53.0		 5.9
45.0
49.1		 17.9
21.3
60.8		 3.8
32.0
64.3
Age at first childbirth <22
22-29
≥30		 30.3
53.2
6.1		 20.6
62.1
6.9		 32.8
52.3
4.8		 29.5
56.2
7.7
Number of pregnancies 0
1
2
≥3		 10.0
21.6
50.3
18.1		 10.1
21.3
50.3
18.3		 10.0
22.1
43.4
24.4		 6.5
23.9
44.7
24.9
Months of breast feeding 0
<6
≥6		 10.0
61.3
28.4		 10.1
42.5
47.4		 10.0
61.3
28.5		 6.4
61.5
32.0
Family history of breast cancer No
Yes
88.0
12.0
 91.2
8.8		 81.7
18.2		 93.4
6.6
Smoking status, active smokers Non smokers
<10 cigarettes/day
≥10 cigarettes/day		 43.2
22.3
34.2		 64.2
15.6
20.2		 56.6
16.8
26.6		 69.5
11.8
18.5
Passive smoking, smoking husband Non smoker husband
<20 cigarettes/day
≥20 cigarettes/day		 38.4
24.8
35.2		 62.4
18.9
23.5		 44.5
24.3
25.4		 68.8
17.7
12.5
Alcohol consumptionǂ Never
≤1 drink/week
≥2 drinks/week		 34.8
42.3
22.3		 34.3
50.5
14.9		 46.9
37.0
15.5		 53.8
37.2
8.9
Red meat consumption ≤2 servings/week
≥3 servings/week		 69.3
30.3		 74.1
18.7		 73.7
26.1		 66.2
23.4
Animal fat consumption ≤2 times/week
≥3 times/week		 13.5
86.1		 19.4
80.6		 19.3
80.5		 25.9
73.9
Vegetables consumption ≤4 servings/week
≥5 servings/week		 51.0
48.4		 39.4
60.4		 49.3
50.2		 36.7
62.6
Fruits consumption (included juices) <5 servings/week
≥5 servings/week		 34.0
66.0		 24.4
75.4		 35.4
61.1		 24.7
74.8
Intake of vitamins No
Yes		 22.3
77.3		 16.0
84.0		 24.6
75.5		 14.8
85.1
Stress experience No
Yes		 47.7
52.3		 58.3
41.7		 39.8
60.2		 51.0
49.0
OCP use No
Yes		 73.9
26.1		 81.0
18.9		 86.9
13.1		 88.8
11.2
HRT No
Yes		 62.2
37.8		 61.0
39.0
Education level Elementary school
Middle school
High school (university, academy)		 27.1
37.7
35.2		 13.7
34.3
52.0		 32.5
40.5
27.0		 30.8
35.4
33.8
One alcoholic drink, tin of beer or a small bottle, 125 of vine or 30 g of high-grade alcohols. OCP - oral contraceptive; HRT-hormonal replacement therapy; BMI - body mass index. Due to missing values, some categories do not sum to 100%.