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Table 1 Baseline cohort characteristics
| Variable | N | (%) |
|---|---|---|
| Age (yrs)* | 50.6 | ± 7.7 |
| Race | ||
| White | 2,964 | 73.4% |
| Black | 700 | 17.3% |
| Other | 373 | 9.3% |
| Number of pregnancies | ||
| 0 | 322 | 8.0% |
| 1–2 | 1,037 | 25.7% |
| 3–4 | 1,349 | 33.4% |
| >4 | 1,329 | 32.9% |
| Education level | ||
| Illiterate | 259 | 6.5% |
| Between 1 and 7 years of schooling | 2.238 | 56.5% |
| Between 8 and 11 years of schooling | 1.380 | 34.9% |
| College degree | 83 | 2.1% |
| Body Mass Index | ||
| <25 | 1,062 | 26.3% |
| 25–30 | 1,502 | 37.2% |
| 30–40 | 1,320 | 32.7% |
| >40 | 153 | 3.8% |
| Age at first delivery (yrs)* | 21.4 | ± 5.1 |
| Menopause after 55 yrs old† | 88 | 4.4% |
| Menarche before 12 yrs old | 872 | 21.6% |
| History of HRT use | 485 | 12.0% |
| History of OC use | 3,331 | 82.5% |
| Smoking status | ||
| Current smoker | 1,170 | 29.0% |
| Former smoker | 393 | 9.7% |
| No historry | 2,474 | 61.3% |
| First-degree relative with history of cancer (any site) | 1,395 | 33.7% |
| First-degree relative with history of breast or ovary cancer | 248 | 6.1% |
| Previous breast biopsy | 154 | 3.8% |
