Table 1. Baseline characteristics of the analytic sample, excluded PEPI participants, and excluded PEPI-MDS participants.
| Characteristic | Analytic sample (complete baseline and 12-mo mammographic density and serum E1S information), n = 428 | Excluded PEPI-MDS participants (incomplete E1S or mammographic density or assignment to placebo arm), n = 166* | ||
|---|---|---|---|---|
| Mean (SD) | n (frequency) | Mean (SD) | n (frequency) | |
| Age (y) | 56.2 (4.2) | 55.6 (4.6) | ||
| Years since menopause (mean)† | 5.7 (2.7) | 5.5 (2.6) | ||
| BMI (kg/m2) | 25.9 (4.4) | 26.7 (4.6) | ||
| Prior use of hormone therapy‡ | 244 (57.0) | 85 (51.2) | ||
| Recency of hormone therapy use (mo)§ | 23.4 (43.7) | 28.4 (50.8) | ||
| No. pregnancies resulting in live births | 3.2 (1.7) | 3.1 (1.8) | ||
| Smoking | ||||
| Current | 51 (11.9) | 26 (15.7) | ||
| Former | 155 (36.2) | 70 (42.2) | ||
| Never | 222 (51.9) | 70 (42.2) | ||
| Alcohol use (g/d) | 6.3 (12.6) | 6.5 (12.0) | ||
| Level of physical activity‖ | ||||
| Low | 282 (65.9) | 118 (71.1) | ||
| Medium | 143 (33.4) | 46 (27.7) | ||
| High | 3 (0.7) | 2 (1.2) | ||
| Nonwhite ethnicity | 45 (10.5) | 27 (16.3) | ||
| Adherence to treatment assignment¶ | 385 (90.0) | 134 (80.7) | ||
| Hysterectomy** | 129 (30.1) | 50 (30.1) | ||
| Baseline mammographic density (median %, interquartile range)†† | 24 (27) | 24 (30) | ||
| Baseline E1S level nmol/L, mean (SD) | 1.80 (0.84) | 2.45 (2.11) | ||
We excluded data from 51 PEPI-MDS participants who did not have complete baseline and follow-up information on mammographic density and E1S level, 105 participants assigned to placebo, and 10 participants with extreme outlying values for baseline E1S or 12-mo change in E1S.
The last menstrual period for women who reported having a hysterectomy with bilateral oophorectomy was the date of the hysterectomy.
Women were allowed to enroll in PEPI-MDS if they discontinued menopausal hormone therapy for at least 2 mo before the first screening visit.
Months elapsed since menopausal hormone therapy use (based on self-reported date of last use) in those participants who reported prior use of hormone therapy.
Self-reported activity was scored as 1 (inactive), 2 (light), 3 (moderate), or 4 (heavy) for each domain of exercise (leisure and home), and the overall score was calculated as 1/2 of leisure plus home scores minus 1. Categorized as low (≤1.5), medium (≥1.5 and <3), or high (≥3).
Adherence with at least 80% of study medication at both 6- and 12-mo follow-up visits.
Surgical removal of the uterus, with or without oophorectomy.
Percentage of the breast area that is dense, determined using the semiautomated interactive threshold method of Ursin and colleagues (15).