Table 3.
Odds ratios (ORs) and 95% confidence intervals (95% CI) for the association between other established risk factors and young-onset invasive and DCIS breast cancer, Two Sister Study (2008–2010)
| Characteristics | Control Sisters (n=1648) No. (%) |
Invasive Cases (n=1185) No. (%) |
DCIS Cases (n=221) No. (%) |
Adjusted OR All cases vs. controls (95% CI) |
Adjusted OR invasive cases vs. controls (95% CI) |
Adjusted OR DCIS cases vs. control (95% CI) |
Homogeneity p-valuea |
|---|---|---|---|---|---|---|---|
| Heighta | |||||||
| <64 inches | 491 (30) | 343 (29) | 60 (27) | 0.96 (0.78, 1.18) | 0.94 (0.75, 1.17) | 1.11 (0.65, 1.90) | p= 0.90 |
| 64–66.9 inches | 692 (42) | 494 (42) | 101 (46) | 1.00 | 1.00 | 1.00 | |
| ≥67 inches | 465 (28) | 348 (29) | 60 (27) | 1.03 (0.84, 1.25) | 1.02 (0.82, 1.26) | 1.14 (0.68, 1.91) | |
| Trend test | p = 0.59 | p = 0.57 | p = 0.93 | ||||
| Body mass index ages 30–39b | |||||||
| <24.9 kg/m2 | 1191 (72) | 851 (72) | 171 (77) | 1.00 | 1.00 | 1.00 | |
| 25.0–29.9 kg/m2 | 310 (19) | 245 (21) | 36 (16) | 1.03 (0.82, 1.29) | 1.06 (0.83, 1.34) | 0.97 (0.47, 2.01) | p= 0.63 |
| ≥30.0 kg/m2 | 143 (9) | 83 (7) | 14 (6) | 0.74 (0.51, 1.03) | 0.71 (0.48, 1.04) | 1.06 (0.40, 2.83) | |
| Trend test | p = 0.26 | p = 0.33 | p = 0.94 | ||||
| Alcohol use in the 10 years preceding index agec | |||||||
| Nondrinker | 149 (9) | 133 (11) | 19 (9) | 1.00 | 1.00 | 1.00 | |
| Social (<10 drinks/year) | 174 (11) | 92 (8) | 18 (8) | 0.61 (0.42, 0.89) | 0.57 (0.38, 0.85) | 1.03 (0.40, 2.69) | |
| 10–38 drinks/year | 434 (26) | 322 (27) | 65 (29) | 0.81 (0.59, 1.12) | 0.72 (0.52, 1.02) | 1.80 (0.79, 4.10) | p= 0.42 |
| 39–161 drinks/year | 451 (27) | 327 (28) | 63 (29) | 0.77 (0.56, 1.05) | 0.66 (0.47, 0.94) | 1.68 (0.74, 3.82) | |
| ≥161 drinks/year | 437 (27) | 310 (26) | 56 (25) | 0.72 (0.52, 1.00) | 0.64 (0.45, 0.91) | 1.44 (0.59, 3.51) | |
| Trend test | p = 0.22 | p = 0.08 | p = 0.33 | ||||
| Smoking history as of index aged | |||||||
| Non-smoker | 1080 (66) | 758 (64) | 150 (68) | 1.00 | 1.00 | 1.00 | |
| Former smoker | 388 (24) | 304 (26) | 54 (24) | 1.13 (0.92, 1.40) | 1.24 (0.98, 1.56) | 0.68 (0.40, 1.16) | p= 0.21 |
| Current smoker | 177 (11) | 122 (10) | 17 (8) | 0.94 (0.69, 1.26) | 0.96 (0.69, 1.33) | 0.75 (0.33, 1.70) | |
Abbreviations: Odds Ratio (OR), 95% Confidence Interval (95% CI), Ductal Carcinoma in situ (DCIS)
The following variables had missing data: Body mass index (4 controls, 6 invasive cases), Alcohol use (20 controls, 1 invasive case), Smoking history (3 controls, 1 invasive case). 13 cases were missing invasive status were removed, along with their 17 matched controls.
Adjusted for education
Adjusted for education, childhood physical activity, alcohol (ever/never), smoking (ever/never), parous at age 30 (yes/no), age at menarche, birth order
Adjusted for education, birth order, smoking (ever/never)
Adjusted for education, alcohol use (ever/never), birth order