Table 1.

Baseline characteristics of the analytic sample, excluded PEPI participants, and excluded PEPI-MDS participants

CharacteristicAnalytic 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 therapy244 (57.0)85 (51.2)
Recency of hormone therapy use (mo)§23.4 (43.7)28.4 (50.8)
No. pregnancies resulting in live births3.2 (1.7)3.1 (1.8)
    Current51 (11.9)26 (15.7)
    Former155 (36.2)70 (42.2)
    Never222 (51.9)70 (42.2)
Alcohol use (g/d)6.3 (12.6)6.5 (12.0)
Level of physical activity
    Low282 (65.9)118 (71.1)
    Medium143 (33.4)46 (27.7)
    High3 (0.7)2 (1.2)
Nonwhite ethnicity45 (10.5)27 (16.3)
Adherence to treatment assignment385 (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).