|
Characteristics
|
No. of subjects
|
No. of cases
|
Person years
|
Incidence (/100,000 PYs)
|
HR (95% CI)
|
|---|
|
All subjects
|
14464
|
66
|
34001
|
194
|
—
|
|
Age (yrs.)
|
|
< 40
|
1020
|
0
|
2122
|
0
|
—
|
|
40-
|
2833
|
9
|
6848
|
131
|
0.60 (0.28, 1.27)
|
|
50-
|
5349
|
29
|
13200
|
220
|
1.00 (ref.)
|
|
60-
|
4213
|
23
|
9712
|
237
|
1.07 (0.62, 1.85)
|
|
70-
|
1049
|
5
|
2118
|
236
|
1.05 (0.40, 2.72)
|
|
Education
|
|
Primary school or No formal education
|
3324
|
17
|
8940
|
190
|
1.23 (0.62, 2.44)
|
|
Junior middle school
|
5646
|
18
|
13361
|
135
|
1.00 (ref.)
|
|
Senior high school or technical school
|
3739
|
21
|
8099
|
259
|
1.86 (0.99, 3.49)
|
|
Junior college
|
1018
|
6
|
2148
|
279
|
2.44 (0.96, 6.19)
|
|
Regular college or above
|
737
|
4
|
1454
|
275
|
2.91 (0.97, 8.72)
|
|
Family history of breast cancer
|
|
Yes
|
366
|
5
|
858
|
583
|
3.03 (1.22, 7.54)
|
|
No
|
14098
|
61
|
33143
|
184
|
1.00 (ref.)
|
|
Age at menarche (yrs.)
|
|
≤ 13
|
2078
|
15
|
4582
|
327
|
1.99 (1.10, 3.58)
|
|
14-17
|
10330
|
44
|
24273
|
181
|
1.00 (ref.)
|
|
> 17
|
2053
|
7
|
5142
|
136
|
0.66 (0.29, 1.47)
|
|
Menopausal status
|
|
Pre-menopause
|
4455
|
12
|
10510
|
114
|
0.81 (0.32, 2.04)
|
|
Post-menopause
|
9996
|
54
|
23462
|
230
|
1.00 (ref.)
|
|
Age at menopause (yrs.)
|
|
< 45
|
721
|
4
|
1704
|
235
|
1.12 (0.41, 3.11)
|
|
45-54
|
8323
|
44
|
19523
|
225
|
1.00 (ref.)
|
|
≥ 55
|
952
|
6
|
2234
|
269
|
1.20 (0.51, 2.81)
|
|
Age at first live birth (yrs.)
|
|
Nulliparity
|
299
|
0
|
643
|
0
|
—
|
|
< 24
|
3290
|
13
|
7940
|
164
|
0.99 (0.51, 1.92)
|
|
24-29
|
9121
|
39
|
21691
|
180
|
1.00 (ref.)
|
|
≥ 30
|
1750
|
14
|
3718
|
377
|
2.01 (1.09, 3.71)
|
- Missing values were excluded from the analysis (3 subjects for age at menarche, 13 for menopause status and 4 for age at first live birth).
