Table 1.Baseline characteristics of cases and controls
Variable |
Case (n = 3242) |
Control (n = 1818) |
p-value1
|
Age (y)2
|
48.0 (10.0) |
48.3 (11.8) |
0.31 |
Body mass index (kg/m2)2
|
23.1 (3.0) |
48.3 (3.0) |
0.38 |
Education ≥15 y3
|
1078 (33.3) |
598 (32.1) |
0.86 |
Family history of breast cancer present |
176 (5.4) |
67 (3.7) |
0.01 |
Ever had breast examination |
1984 (61.5) |
1225 (67.6) |
<0.01 |
Post-menopause |
1246 (38.8) |
853 (47.1) |
<0.01 |
Age of menarche (y)2
|
15.0 (1.7) |
15.2 (1.8) |
<0.01 |
Ever pregnant |
2957 (91.2) |
1597 (87.8) |
<0.01 |
Age of first pregnancy (y)4
|
23.8 (8.1) |
22.6 (9.0) |
<0.01 |
Ever breastfed4
|
2312 (71.7) |
1296 (71.4) |
0.78 |
Number of children2
|
2.02 (1.1) |
2.0 (1.2) |
0.69 |
Ever drank alcohol |
1194 (36.8) |
652 (35.9) |
0.50 |
Ever smoked |
241 (7.4) |
103 ( 5.7) |
0.02 |
Table 2.Association of pre-existing medical conditions with breast cancer incidence1
Diseases |
Case |
Control |
cOR (95% CI) |
aOR1 (95% CI) |
Tuberculosis |
135 (4.16) |
67 (3.69) |
1.14 (0.84, 1.53) |
1.10 (0.92, 1.33) |
Diabetes |
100 (3.08) |
34 (1.87) |
1.67 (1.13, 2.47) |
1.33 (0.99, 1.78) |
Gastroduodenal disease |
107 (3.30) |
79 (4.35) |
0.75 (0.56, 1.01) |
0.97 (0.82, 1.14) |
Liver disease |
62 (1.91) |
23 (1.27) |
1.52 (0.94, 2.46) |
1.23 (0.94, 1.61) |
Hypertension |
287 (8.85) |
104 (5.72) |
1.60 (1.27, 2.02) |
1.46 (1.18, 1.83) |
Asthma |
46 (1.42) |
43 (2.37) |
0.59 (0.39, 0.90) |
0.98 (0.82, 1.18) |
Thyroid disease |
163 (5.03) |
65 (3.58) |
1.43 (1.07, 1.91) |
1.26 (1.00, 1.58) |
Ovarian disease |
149 (4.60) |
39 (2.15) |
2.20 (1.54, 3.14) |
1.70 (1.23, 2.35) |
Table 3.Association between comorbidity and breast cancer incidence in a population stratified by menopausal status
Diseases |
Pre-menopause (n = 2925)
|
Post-menopause (n = 2099)
|
p-heterogeneity |
Case |
Control |
aOR1 (95% CI) |
Case |
Control |
aOR1 (95% CI) |
Tuberculosis |
80 (4.1) |
43 (4.5) |
0.82 (0.56, 1.20) |
54 (4.3) |
24 (2.8) |
1.20 (0.94, 1.54) |
0.10 |
Diabetes |
18 (0.9) |
4 (0.4) |
1.85 (0.62, 5.50) |
82 (6.6) |
30 (3.5) |
1.44 (1.03, 2.01) |
0.67 |
Gastroduodenal disease |
62 (3.2) |
38 (4.0) |
0.75 (0.49, 1.14) |
44 (3.5) |
41 (4.8) |
1.04 (0.86, 1.25) |
0.17 |
Liver disease |
30 (1.5) |
9 (0.9) |
1.67 (0.78, 3.58) |
31 (2.5) |
14 (1.6) |
1.18 (0.92, 1.51) |
0.40 |
Hypertension |
50 (2.5) |
23 (2.4) |
0.80 (0.48, 1.34) |
236 (18.9) |
81 (9.5) |
1.87 (1.44, 2.43) |
<0.01 |
Asthma |
27 (1.4) |
20 (2.1) |
0.71 (0.39, 1.30) |
19 (1.5) |
23 (2.7) |
1.04 (0.86, 1.27) |
0.24 |
Thyroid disease |
82 (4.2) |
27 (2.8) |
1.44 (0.92, 2.25) |
80 (6.4) |
38 (4.5) |
1.24 (0.97, 1.59) |
0.57 |
Ovarian disease |
63 (3.2) |
7 (0.7) |
4.20 (1.91, 9.24) |
86 (6.9) |
32 (3.8) |
1.39 (1.02, 1.91) |
0.01 |