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Characteristics of women by breast density category, and odds ratios for association with denser breast category (n = 157) |
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| Characteristic |
Entirely fatty (n = 20) |
Heterogeneously dense (n = 44) |
Scattered fibroglandular tissue (n = 54) |
Extremely dense (n = 39) |
Age-adjusted odds ratio (95% confidence interval)a |
|
|
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| Age (years) |
54.1 ± 1.0 |
53.9 ± 0.9 |
48.7 ± 0.6 |
47.4 ± 0.7 |
0.4 (0.3–0.6)b |
| College graduate (%)c |
55 |
72 |
72 |
84 |
1.5 (0.8–3.0) |
| Body mass index (kg/m2) |
33.3 ± 7.1 |
28.3 ± 6.1 |
24.8 ± 4.4 |
23.8 ± 3.0 |
0.8 (0.8–0.9) |
| Age at menarche (years) |
12.4 ± 1.3 |
12.3 ± 1.3 |
12.5 ± 1.4 |
13.1 ± 1.8 |
1.3 (1.1–1.6) |
| Number of live birthsc |
3.1 ± 1.4 |
2.5 ± 1.6 |
2.6 ± 0.9 |
1.9 ± 1.0 |
0.8 (0.6–1.0) |
| Age at first birth (years)c |
23.7 ± 5.9 |
25.6 ± 4.1 |
27.4 ± 5.8 |
29.5 ± 5.1 |
1.1 (1.0–1.2) |
| Ever breastfedc |
30 |
72 |
63 |
75 |
1.0 (0.4–2.7) |
| Postmenopausal |
65 |
66 |
33 |
28 |
0.5 (0.3–1.2) |
| Ever used hormonal contraceptives |
45 |
41 |
63 |
37 |
0.8 (0.5–1.4) |
| Ever used hormone replacement medicined |
85 |
45 |
56 |
36 |
0.4 (0.2–1.0) |
| Weekly physical activity (hours) |
2.9 ± 2.9 |
3.6 ± 3.0 |
3.5 ± 2.9 |
2.9 ± 2.5 |
1.0 (0.8–1.1) |
| Smoking status |
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| ∘ Never smoked |
50 |
49 |
57 |
61 |
1.0 |
| ∘ Former smoker |
45 |
49 |
39 |
26 |
0.6 (0.3–1.1) |
| ∘ Current smoker |
5 |
2 |
4 |
13 |
2.0 (0.5–7.6) |
| Family history of breast cancer |
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| ∘ Negative or sporadic |
15 |
30 |
22 |
10 |
1.0 |
| ∘ Familial |
35 |
45 |
33 |
33 |
1.3 (0.6–2.9) |
| ∘ Hereditary |
50 |
25 |
44 |
56 |
1.8 (0.8–4.0) |
|
Characteristics data presented as the mean ± standard deviation or as the percentage. aOdds ratios adjusted for age except for the age variable. bOdds ratio for 10-year age increment. c Because of missing responses, analyses included only 155 women for education level, 125 women for number of live births, 120 parous women for age at first live birth, and 74 parous women for breastfeeding. dAnalysis conducted among 70 postmenopausal women. | |||||
Tseng et al. Breast Cancer Research 2007 9:R72 doi:10.1186/bcr1781 |
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