| |
Number of
|
Number of
|
Number of
|
Pb
|
|---|
|
Cases
|
Ctrls
|
ORa
|
95% CI
|
Cases
|
Ctrls
|
ORa
|
95% CI
|
Cases
|
Ctrls
|
ORa
|
95% CI
|
|---|
|
Birth cohort
|
|---|
|
≤ 1945
|
1946–1959
|
≥ 1960
|
|---|
|
Chest X-ray exposure
|
|
No
|
47
|
31
|
1
| |
96
|
92
|
1
| |
65
|
116
|
1
| | |
|
Yes
|
431
|
259
|
1.57
|
0.72-3.43
|
678
|
605
|
1.65
|
1.06–2.56
|
195
|
240
|
2.54
|
1.63–3.98
|
0.024
|
|
Number of exposures
|
|
0
|
47
|
31
|
1
| |
96
|
92
|
1
| |
65
|
116
|
1
| | |
|
1–3
|
134
|
81
|
1.72
|
0.74–3.98
|
179
|
197
|
1.24
|
0.75–2.05
|
79
|
112
|
2.04
|
1.22–3.40
| |
|
4–9
|
81
|
46
|
2.04
|
0.82–5.07
|
122
|
111
|
1.70
|
0.98–2.94
|
48
|
43
|
3.77
|
2.03–7.01
|
0.041
|
|
≥10
|
105
|
64
|
1.44
|
0.60–3.45
|
142
|
130
|
2.26
|
1.31–3.90
|
16
|
21
|
2.77
|
1.19–6.47
| |
|
Continuous
| | |
1.01
|
0.99–1.03
| | |
1.04
|
1.02–1.06
| | |
1.06
|
1.01–1.12
|
0.013
|
|
Age at first exposure, yearsc
|
|
No exposure
|
47
|
31
|
0.52
|
0.23–1.21
|
96
|
92
|
0.77
|
0.47–1.25
|
65
|
116
|
0.47
|
0.28–0.78
| |
|
≥20
|
163
|
119
|
1
| |
237
|
261
|
1
| |
85
|
110
|
1
| | |
|
15–19
|
87
|
45
|
0.74
|
0.38–1.42
|
159
|
123
|
1.07
|
0.69–1.66
|
42
|
54
|
1.13
|
0.64–2.00
|
0.67
|
|
<15
|
122
|
64
|
0.83
|
0.47–1.46
|
140
|
114
|
1.40
|
0.89–2.18
|
28
|
41
|
0.91
|
0.47–1.79
| |
|
Continuous
| | |
1.01
|
0.99–1.02
| | |
1.00
|
0.98–1.01
| | |
1.02
|
0.99–1.05
|
0.49
|
|
According to first full-term pregnancy (FFTP)c
|
|
Only after FFTPd
|
109
|
59
|
1
| |
124
|
139
|
1
| |
35
|
34
|
1
| | |
|
Before (incl. no FTP)
|
268
|
175
|
0.48
|
0.27–0.86
|
429
|
373
|
0.95
|
0.63–1.44
|
128
|
177
|
0.86
|
0.45–1.63
|
0.19
|
- Abbreviations: OR (95% CI) odds ratio (95% confidence interval
- aAdjusted for age at censoring (when by birth cohort analysis) and for birth cohort (continuous) (when by age at censure analysis), number of full-term pregnancies (>2; 1–2; 0), mammography use (never; ever), educational level (intermediate/high; basic; not graduated), BMI (18.5–24.99; <18.5; ≥25 and <30; ≥30), smoking (no; current; past), and family history of breast cancer (0;1st degree; 2nd degree)
- bP value for heterogeneity test
- cAdjusted as in a plus number of exposures (≤5; >5)
- dAfter = also includes chest X-ray exposure that occurred during year of first full-term pregnancy
