Introduction
Methods
Study population
Data collection
Controls (n = 685) | Cases (n = 414) | |||
---|---|---|---|---|
Age, years at mammography
| ||||
Mean (SD) | 59.5 (6.6) | 67.5 (12.7) | ||
Missing, n | 6 | 2 | ||
Ethnicity
| ||||
White, n (%) | 520 (76.5) | 370 (90.5) | ||
Other, n (%) | 160 (23.5) | 39 (9.5) | ||
Missing, n | 5 | 5 | ||
Educational level
| ||||
None, n (%) | 15 (2.2) | 10 (3.7) | ||
Primary, n (%) | 20 (3.0) | 7 (2.6) | ||
Secondary, n (%) | 297 (43.9) | 186 (68.4) | ||
University, n (%) | 344 (50.9) | 69 (25.4) | ||
Missing, n | 9 | 142 | ||
Body mass index at mammography
a
, kg/m
2
| ||||
Mean (SD) | 26.1 (5.6) | 26.4 (4.9) | ||
Missing, n | 29 | 46 | ||
Age at menarche, yrs
| ||||
<12, n (%) | 141 (21.0) | 81 (21.3) | ||
12, n (%) | 130 (19.4) | 78 (20.5) | ||
13, n (%) | 168 (25.0) | 87 (22.8) | ||
14+, n (%) | 232 (34.6) | 135 (35.4) | ||
Missing, n | 14 | 33 | ||
Menopausal status at mammography
b
| ||||
Pre- and perimenopausal, n (%) | 91 (13.3) | 55 (13.3) | ||
Postmenopausal, n (%) | 591 (86.7) | 358 (86.7) | ||
Missing, n | 3 | 1 | ||
Ever use of oral contraceptives
| ||||
Yes, n (%) | 472 (70.5) | 216 (55.2) | ||
No, n (%) | 198 (29.6) | 175 (44.8) | ||
Missing, n | 15 | 23 | ||
Ever use of hormonal therapy
| ||||
Yes, n (%) | 208 (31.2) | 143 (36.8) | ||
No, n (%) | 459 (68.8) | 246 (63.2) | ||
Missing, n | 18 | 25 | ||
Nulliparity
| ||||
No, n (%) | 467 (69.1) | 343 (84.1) | ||
Yes, n (%) | 209 (30.9) | 65 (15.9) | ||
Missing, n | 9 | 6 | ||
Number of children
c
, n (%)
| ||||
1 to 2 | 301 (65.4) | 218 (64.9) | ||
2 to 3 | 126 (27.4) | 105 (31.3) | ||
5+ | 33 (7.2) | 13 (3.9) | ||
Age at first birth, yrs
c
, n (%)
| ||||
<20 | 83 (18.1) | 25 (7.7) | ||
20 to 30 | 258 (56.3) | 213 (65.7) | ||
30+ | 117 (25.6) | 86 (26.5) | ||
Ever breastfed
c
, n (%)
| ||||
Yes | 358 (77.2) | 224 (74.7) | ||
No | 106 (22.8) | 76 (25.3) |
Statistical methods
Results
Inter- and intra-method comparisons among controls
Associations with breast cancer risk factors among controls
Breast cancer risk
Area-based methods | Volumetric-based methods | ||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Cumulus | ImageJ-based method | Volpara | Quantra | SXA | |||||||||||
Percent density | Number | ORa | (95% CI) | Number | ORa | (95% CI) | Number | ORa | (95% CI) | Number | ORa | (95% CI) | Number | ORa | (95% CI) |
Average of CC and MLO readingsb | 1,010 |
1.58
| (1.33, 1.88) | 891 |
1.45
| (1.21, 1.74) | 1,010 |
1.83
| (1.51, 2.21) | - | - | - | - | - |
-
|
Only CC readingsb | 1,009 |
1.57
| (1.32, 1.87) | 888 |
1.33
| (1.11, 1.59 | 1,009 |
1.75
| (1.45, 2.10) | 975 |
1.40
| (1.19, 1.66) | 934 |
1.37
|
(1.16, 1.63)
|
Only MLO readingsb | 1,008 |
1.56
| (1.31, 1.85) | 882 |
1.42
| (1.19, 1.69) | 1,008 |
1.75
| (1.44, 2.11) | - | - |
-
| |||
Multiple imputationc | 1,095 |
1.63
| (1.37, 1.93) | 971 |
1.45
| (1.22, 1.73) | 1,095 |
1.82
| (1.51, 2.20) | 1,057 |
1.40
| (1.19, 1.64) | 1,014 |
1.35
|
(1.15, 1.60)
|
Restricted to women aged <80 yrs | 948 |
1.58
| (1.32, 1.88) | 830 |
1.44
| (1.20, 1.72) | 948 |
1.78
| (1.47, 2.15) | 914 |
1.38
| (1.17, 1.63) | 874 |
1.36
|
(1.15, 1.62)
|
Restricted to women with data for all quantitative methods | 797 |
1.55
| (1,29, 1.87) | 797 |
1.52
| (1.26, 1.84) | 797 |
1.64
| (1.33, 2.02) | 797 |
1.26
| (1.05, 1.55) | 797 |
1.48
|
(1.22, 1.80)
|
Dense area/volume
|
Number
|
OR
a
|
(95% CI)
|
Number
|
OR
a
|
(95% CI)
|
Number
|
OR
|
(95% CI)
|
Number
|
OR
|
(95% CI)
|
Number
|
OR
|
(95% CI)
|
Average of CC and MLO readingsb | 1,010 |
1.57
| (1.33, 1.84) | 891 |
1.56
| (1.31, 1.84) | 1,010 |
1.46
| (1.25, 1.70) | - | - | - | - | - | - |
Only CC readingsb | 1,009 |
1.58
| (1.35, 1.86) | 888 |
1.45
| (1.23, 1.71) | 1,009 |
1.47
| (1.26, 1.72) | 975 |
1.04
| (0.88, 1.22) | 934 |
1.26
| (1.08, 1.47) |
Only MLO readingsb | 1,008 |
1.52
| (1.30, 1.79) | 882 |
1.49
| (1.26, 1.77) | 1,008 |
1.38
| (1.18, 1.61) | - | - | - | |||
Multiple imputationc | 1,095 |
1.60
| (1.36, 1.87) | 971 |
1.54
| (1.31, 1.82) | 1,095 |
1.43
| (1.23, 1.66) | 1,057 |
1.02
| (0.87, 1.19) | 1,014 |
1.23
| (1.05, 1.43) |
Restricted to women aged <80 yrs | 948 |
1.57
| (1.33, 1.84) | 830 |
1.54
| (1.31, 1.82) | 948 |
1.49
| (1.27, 1.74) | 914 |
1.06
| (0.89, 1.26) | 874 |
1.27
| (1.08, 1.49) |
Restricted to women with data for all quantitative methods | 797 |
1.63
| (1.36, 1.95) | 797 |
1.62
| (1.36, 1.94) | 797 |
1.70
| (1.42, 2.04) | 797 |
1.23
| (1.02, 1.49) | 797 |
1.74
| (1.43, 2.11) |
Non-dense area/volume
|
Number
|
OR
|
(95% CI)
|
Number
|
OR
|
(95% CI)
|
Number
|
OR
|
(95% CI)
|
Number
|
OR
|
(95% CI)
|
Number
|
OR
|
(95% CI)
|
Average of CC and MLO readingsb | 1,010 |
0.69
| (0.57, 0.84) | 891 |
1.13
| (0.93, 1.37) | 1,010 |
0.85
| (0.71, 1.03) | - | - | - | - | - | - |
Only CC readingsb | 1,009 |
0.74
| (0.61, 0.90) | 888 |
1.15
| (0.95, 1.40) | 1,009 |
0.88
| (0.73, 1.06) | 975 |
0.80
| (0.66, 0.97) | 934 |
0.90
| (0.75, 1.08) |
Only MLO readingsb | 1,008 |
0.66
| (0.54, 0.80) | 882 |
1.08
| (0.89, 1.30) | 1,008 |
0.84
| (0.69, 1.01) | - | - | - | |||
Multiple imputationc | 1,095 |
0.67
| (0.56, 0.82) | 971 |
1.09
| (0.90, 1.31) | 1,095 |
0.83
| (0.69, 1.01) | 1,057 |
0.78
| (0.65, 0.94) | 1,014 |
0.87
| (0.73, 1.04) |
Restricted to women aged <80 yrs | 948 |
0.69
| (0.57, 0.84) | 831 |
1.13
| (0.93, 1.37) | 948 |
0.88
| (0.72, 1.07) | 914 |
0.82
| (0.68, 1.00) | 874 |
0.91
| (0.76, 1.10) |
Restricted to women with data for all quantitative methods | 797 |
0.93
| (0.74, 1.17) | 797 |
1.12
| (0.91, 1.37) | 797 |
1.10
| (0.88, 1.38) | 797 |
1.03
| (0.83, 1.28) | 797 |
1.01
| (0.81, 1.26) |