Table 1.

Distribution of selected baseline characteristics of WHI participants by baseline CCB use, as compared with other AHM use, in the WHI OS and CT, N = 28,561

CharacteristicsOther AHM use (n = 20,510), n (%)CCB Use (n = 8,051), n (%)
Demographics and anthropometrics
Age, mean (SD)64.97 (6.94)65.36 (7.00)
Education
 ≤High school graduate5,359 (26.32)2,217 (27.72)
 Some college8,133 (39.94)3,111 (38.90)
 College or advanced degree6,870 (33.74)2,670 (33.38)
Race/ethnicity
 White16,527 (80.58)5,679 (70.54)
 Black2,436 (11.88)1,517 (18.84)
 Hispanic611 (2.98)314 (3.90)
 Asian/Pacific Islander510 (2.49)357 (4.43)
 Other426 (2.08)184 (2.29)
Body mass index, kg/m2
 <254,606 (22.66)1,887 (23.64)
 25–29.96,857 (33.73)2,776 (34.77)
 ≥308,867 (43.62)3,320 (41.59)
Lifestyle characteristics
Physical activity, MET-h/week
 Inactive3,706 (18.45%)1,510 (19.17)
 >0–6.76,422 (31.96%)2,494 (31.66)
 6.8–16.65,327 (26.51%)2,094 (26.58)
 ≥16.64,637 (23.08%)1,780 (22.59)
Smoking, pack-years
 Never smoker10,654 (53.75)4,041 (52.03)
 >0–7.43,008 (15.18)1,170 (15.06)
 7.5–23.02,829 (14.27)1,126 (14.50)
 ≥23.13,329 (16.80)1,430 (18.41)
Alcohol consumption, servings/week
 09,792 (47.90)4,116 (51.25)
 0.2–0.83,951 (19.33)1,500 (18.68)
 0.9–3.73,238 (15.84)1,137 (14.16)
 ≥3.83,463 (16.94)1,278 (15.91)
Medical history and reproductive health
Number of first-degree relatives with breast cancer
 None16,177 (85.20)6,428 (85.31)
 12,506 (13.20)995 (13.21)
 ≥2304 (1.60)112 (1.49)
Breast cancer screening
 Never541 (2.65)214 (2.67)
 Ever19,857 (97.35)7,792 (97.33)
Age at menarche, years
 ≤101,464 (7.16)574 (7.15)
 11–128,845 (43.25)3,377 (42.08)
 13–148,249 (40.34)3,277 (40.83)
 ≥151,891 (9.25)797 (9.93)
Age at menopause, years
 <476,983 (35.87)2,877 (37.82)
 47–516,486 (33.31)2,414 (31.73)
 ≥526,001 (30.82)2,317 (30.45)
Parity
 Never pregnant2,239 (10.97)867 (10.83)
 11,764 (8.65)698 (8.72)
 2–412,932 (63.38)5,052 (63.11)
 ≥53,468 (17.00)1,388 (17.34)
Age at first birth, years
 Never pregnant2,239 (12.16)867 (12.07)
 <202,877 (15.62)1,234 (17.18)
 20–2911,876 (64.48)4,545 (63.27)
 ≥301,427 (7.75)537 (7.48)
Duration of unopposed estrogen therapy, years
 <414,628 (71.32)5,823 (72.33)
 4–122,549 (12.43)968 (12.02)
 ≥123,333 (16.25)1,260 (15.65)
Duration of combined hormone therapy, years
 <2.517,419 (84.93)6,992 (86.85)
 2.5–71,507 (7.35)514 (6.38)
 ≥81,584 (7.72)545 (6.77)