Table 1.
Baseline characteristics of study population (N=4051)
| Characteristics at enrollment | Median | Range |
|---|---|---|
| Age, years | 59 | 50–74 |
| Duration of HRT use in months | 60 | 0–624 |
| Duration of OCP use in months | 48 | 0–480 |
|
| ||
| No. | % | |
|
| ||
| Ethnicity | ||
| White | 3315 | 82 |
| African American | 406 | 10 |
| Hispanic | 187 | 5 |
| Asian | 104 | 3 |
| Other | 39 | 1 |
| Ever pregnant | 3168 | 87 |
| Ever use OCP | 2966 | 80 |
| Ever use HRT | 2255 | 61 |
| Hysterectomy | 777 | 21 |
| Personal history of breast cancer | 470 | 14 |
Abbreviations: HRT, hormone replacement therapy; OCP, oral contraceptive pill.