Table 2.

Associations of baseline CCB use versus other AHM use with breast cancer risk in the WHI OS and CT, n = 28,561

Baseline duration of CCB use, yearsa
AHM UseCCB Use>0–4.95.0–9.9≥10
Any CCBs
n cases/n noncases1,008/19,502394/7,657256/5,349103/1,60135/707
 HR (95% CI)b1.00 reference1.06 (0.94–1.20)1.01 (0.87–1.18)1.33 (1.03–1.71)1.05 (0.72–1.52)
CCB Action
 Short acting
  n cases/n noncases1,008/19,502112/2,13972/1,50632/4508/192
  HR (95% CI)b1.00 reference1.08 (0.88–1.32)1.03 (0.80–1.32)1.35 (0.91–2.02)0.91 (0.44–1.86)
 Long acting
  n cases/n noncases1,008/19,502284/5,548184/3,87873/1,15927/520
  HR (95% CI)b1.00 reference1.06 (0.92–1.22)0.99 (0.84–1.18)1.33 (1.00–1.76)1.08 (0.71–1.63)
CCB Drug class
 Dihydropyridines
  n cases/n noncases1,008/19,502152/3,390118/2,61424/56410/212
  HR (95% CI)b1.00 reference0.96 (0.81–1.15)1.00 (0.81–1.22)0.87 (0.56–1.36)0.92 (0.48–1.78)
 Nondihydropyridines
  n cases/n noncases1,008/19,502242/4,300138/2,76579/1,03925/496
  HR (95% CI)b1.00 reference1.13 (0.98–1.31)1.01 (0.83–1.23)1.54 (1.17–2.02)1.09 (0.71–1.66)
  • aRelative to the same duration of other AHM use; case/noncase frequencies for other AHM users are: 610/12,184 (>0–4.9 y), 189/3,654 (5.0–9.9 y), and 209/3,664 (≥10 y).

  • bAdjusted for baseline age (time variable), WHI-CT intervention assignment, education, race, body mass index, physical activity, smoking, alcohol, and breast cancer screening.