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. 2016 Dec 12;4(4):E754–E759. doi: 10.9778/cmajo.20160046

Table 1: Relative risks of cancers associated with use of oral contraceptives and hormone therapy.

Exposure Cancer site Detailed exposure Risk estimate (95% CI) Source
Oral contraceptives
Breast Ever use 1.08 (1.00-1.17) Gierisch et al. 20132
Endometrium Ever use 0.57 (0.43-0.77) Gierisch et al. 20132
Ovary Ever use 0.73 (0.66-0.81) Havrilesky et al. 20133
Hormone therapy* Breast Ever use 1.39 (1.12-1.72) Shah et al. 20055
Breast Current use 1.66 (1.58-1.75) Beral 200327
Endometrium Ever use 0.78 (0.72-0.86) Brinton et al. 20146
Endometrium Current use 0.75 (0.58-0.97) Beral et al. 200524
Ovary Ever use 1.20 (1.15-1.26) Beral et al. 20157
Ovary Current use 1.41 (1.32-1.50) Beral et al. 20157

Note: CI = confidence interval.

*Continuous estrogen-progestin combined hormone therapy (progestins were included in the therapy for > 25 d/mo).