Table 1.
Distribution of selected characteristics of breast cancer patients according to oral contraceptive (OC) use status in the Women's Contraceptive and Reproductive Experiences (CARE) Study and the California Teachers Study (CTS).
| Women's CARE Study |
CTS (age 35–64) |
CTS (all) |
||||
|---|---|---|---|---|---|---|
| (N=4565) | (N=2222) | (N=3929) | ||||
| OC use | OC use | OC use | ||||
| Never (N=1041) | Ever (N=3524) | Never (N=395) | Ever (N=1827) | Never (N=1490) | Ever (N=2439) | |
| Age at diagnosis (y) | ||||||
| <35 | 0.1 | 0.3 | ||||
| 35–39 | 7.6 | 17.3 | 1.3 | 2.6 | 0.3 | 1.9 |
| 40–44 | 8.4 | 19.0 | 5.8 | 3.8 | 1.5 | 2.8 |
| 45–49 | 8.7 | 19.6 | 10.9 | 11.2 | 2.9 | 8.4 |
| 50–54 | 15.0 | 19.5 | 19.5 | 22.8 | 5.2 | 17.1 |
| 55–59 | 22.9 | 15.0 | 24.3 | 32.3 | 6.4 | 24.2 |
| 60–64 | 37.6 | 9.6 | 38.2 | 27.4 | 10.1 | 20.5 |
| >64 | 73.4 | 24.8 | ||||
| Race | ||||||
| White | 62.8 | 65.0 | 83.0 | 88.9 | 88.4 | 89.4 |
| Black (CARE)/Other (CTS) | 37.2 | 35.0 | 17.0 | 11.1 | 11.6 | 10.6 |
| Family history of breast cancer (first degree) | ||||||
| No | 77.6 | 79.4 | 76.4 | 80.0 | 79.7 | 79.3 |
| Yes | 17.4 | 16.9 | 19.8 | 17.2 | 17.0 | 17.9 |
| Adopt/Unknown | 5.0 | 3.7 | 3.8 | 2.8 | 3.3 | 2.8 |
| Body Mass Index (kg/m2) * | ||||||
| <20 | 8.3 | 11.4 | 9.4 | 9.7 | 7.1 | 8.7 |
| 20–24.9 | 37.6 | 47.7 | 44.6 | 50.5 | 43.4 | 49.6 |
| 25–29.9 | 27.8 | 25.7 | 30.4 | 23.8 | 30.7 | 24.8 |
| ≥30 | 25.8 | 14.7 | 12.9 | 13.7 | 13.4 | 14.0 |
| Unknown | 0.6 | 0.6 | 2.8 | 2.4 | 5.5 | 2.9 |
| Menopausal status | ||||||
| Premenopausal | 24.3 | 52.8 | 38.0 | 41.3 | 10.3 | 31.2 |
| Postmenopausal | 68.1 | 34.3 | 53.9 | 41.2 | 87.5 | 55.3 |
| Unknown | 7.6 | 12.9 | 8.1 | 17.6 | 2.2 | 13.5 |
| Stage | ||||||
| Localized | 62.7 | 59.6 | 67.1 | 64.4 | 70.8 | 66.7 |
| Non-localized | 37.3 | 40.4 | 32.9 | 35.6 | 29.2 | 33.3 |
| Estrogen status | ||||||
| Positive | 64.7 | 57.0 | 73.7 | 72.5 | 73.6 | 72.8 |
| Negative | 21.3 | 30.8 | 12.9 | 14.7 | 11.4 | 14.2 |
| Unknown | 14.0 | 12.2 | 13.4 | 12.8 | 15.0 | 13.0 |
| Study site | ||||||
| Atlanta | 19.3 | 19.3 | ||||
| Seattle | 18.4 | 24.8 | ||||
| Detroit | 15.3 | 14.7 | ||||
| Philadelphia | 20.9 | 13.8 | ||||
| Los Angeles | 26.1 | 27.5 | ||||
| Education | ||||||
| Not a High School Graduate | 16.3 | 6.5 | ||||
| High School Graduate | 34.9 | 27.5 | ||||
| Some College or Technical School | 26.4 | 34.2 | ||||
| College Graduate | 22.3 | 31.8 | ||||
| Socioeconomic status | ||||||
| Lowest quartile | 3.8 | 3.2 | 4.5 | 3.3 | ||
| 2nd quartile | 13.9 | 14.7 | 16.3 | 14.4 | ||
| 3rd quartile | 28.6 | 30.8 | 30.5 | 30.5 | ||
| Highest quartile | 52.9 | 50.4 | 47.6 | 50.7 | ||
| Unknown | 0.8 | 1.0 | 1.1 | 1.1 | ||
*
Body mass index: at 5 years before breast cancer diagnosis for the CARE Study and at cohort entry for the CTS.