Table 1.
Baseline characteristics of women in the PLCO Cancer Screening Trial
| All Women (%) | |
|---|---|
| Study Participants | 70,047 |
| Age at Baseline | 62 (median) |
| Menopause Statusa | |
| Definitely postmenopausal | 69,362 (99.0%) |
| Unsure | 685 (1%) |
| Race/Ethnicity | |
| Non-Hispanic White | 61,954 (88.5%) |
| Non-Hispanic Black | 4,035 (5.8%) |
| Hispanic | 1,121 (1.6%) |
| Asian/Pacific Islander/American Indian | 2,911 (4.2%) |
| Missing | 26 (<0.1%) |
| Education | |
| Less than High School | 4,566 (6.5%) |
| High School Graduate | 44,526 (63.6%) |
| College Graduate | 20,782 (29.7%) |
| Missing | 173 (0.3%) |
| Body Mass Index | |
| <25 kg/m2 | 27,102 (38.7%) |
| 25–29.9 kg/m2 | 23,969 (34.2%) |
| ≥ 30 kg/m2 | 17,213 (24.6%) |
| Missing | 1,763 (2.5%) |
| Family History of Cancer | |
| No | 28,460 (40.8%) |
| Yes | 41,333 (59.2%) |
| Missing | 254 (0.4%) |
| Family History of Thyroid Cancer | |
| No | 67,610 (97.2%) |
| Yes | 470 (0.7%) |
| Missing | 1,967 (2.8%) |
| Cigarette Smoking Status | |
| Never | 39,257 (56.0%) |
| Former | 24,070 (34.4%) |
| Current | 6,701 (9.6%) |
| Missing | 19 (<0.1%) |
| Personal History of Benign Breast Disease | |
| Never diagnosed | 49,302 (70.4%) |
| Ever diagnosed | 19,040 (27.2%) |
| Missing | 1,705 (2.4%) |
| Personal History of Benign Ovarian Tumor or Cyst | |
| Never diagnosed | 58,343 (83.3%) |
| Ever diagnosed | 8,583 (12.3%) |
| Missing | 3,121 (4.5%) |
| Personal History of Endometriosis | |
| Never diagnosed | 61,105 (87.2%) |
| Ever diagnosed | 5,549 (7.9%) |
| Missing | 3,393 (4.8%) |
| Personal History of Uterine Fibroid Tumors | |
| Never diagnosed | 52,275 (74.6%) |
| Ever diagnosed | 15,288 (21.8%) |
| Missing | 2,484 (3.6%) |
a
Based on participant responses to questions about age at last menstrual period, reasons that periods stopped, age at baseline, and surgery for ovary removal or hysterectomy