Article Figures & Tables
Tables
- 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).
- Table 2: Prevalence of oral contraceptive and hormone therapy use in Alberta (Alberta's Tomorrow Project, 2000-2009)
Exposure Age, yr Prevalence
(95% CI)Oral contraceptives: ever use 35-44 92.3 (91.7-93.0) 45-54 91.1 (90.4-91.8) 55-64 85.5 (84.5-86.6) ≥ 65 67.6 (65.3-69.9) Hormone therapy: ever use 35-44 4.4 (3.9-4.9) 45-54 25.2 (24.2-26.3) 55-64 60.3 (58.9-61.7) ≥ 65 60.5 (58.1-62.9) Hormone therapy: current use 35-44 2.8 (2.4-3.3) 45-54 15.5 (14.7-16.4) 55-64 27.2 (25.9-28.5) ≥ 65 19.6 (17.6-21.5) Note: CI = confidence interval.
- Table 3: Observed cancer cases in Alberta (2012) and proportions attributable to use of oral contraceptives and hormone therapy
Age at
exposure, yrAge at
outcome, yrBreast Endometrium Ovary Observed cases* PAR†, % EAC‡ Observed cases* PAR, % EAC Observed cases* PAR, % EAC Oral contraceptives: ever use 35-44 43-52 463 7.0 32 57 -64.8 -37 36 -33.2 -12 45-54 53-62 584 6.9 40 183 -63.4 -116 46 -32.6 -15 55-64 63-72 559 6.5 36 152 -57.3 -87 46 -30.0 -14 ≥ 65 ≥ 73 522 5.2 27 90 -40.4 -36 51 -22.3 -11 Total 2128 135 482 -276 179 -52 Hormone therapy: ever use 35-44 43-52 45-54 53-62 584 9.0 52 183 -5.9 -11 46 4.8 2 55-64 63-72 559 19.0 106 152 -15.3 -23 46 10.8 5 ≥ 65 ≥ 73 522 19.1 100 90 -15.3 -14 51 10.8 6 Total 1665 258 425 -48 143 13 Hormone therapy: current use 35-44 43-52 45-54 53-62 584 9.3 54 183 -4 -7 46 6.0 3 55-64 63-72 559 15.2 85 152 -7.3 -11 46 10.0 5 ≥ 65 ≥ 73 522 11.4 60 90 -5.1 -5 51 7.4 4 Total 1665 199 425 -23 143 12 Note: EAC = excess attributable risk due to exposure, PAR = population attributable risk.
*The values represent the total number of cases of each cancer type diagnosed in 2012. For hormone therapy, only postmenopausal cases of cancer (cancers diagnosed at age 53 yr and older) are included.
†Represents the proportion of cancer cases attributable to oral contraceptive ever use, hormone therapy ever use or hormone therapy current use. The negative values represent preventable proportions of cancer cases owing to protective effect.
‡Represents the number of cases attributable to oral contraceptive ever use, hormone therapy ever use or hormone therapy current use. The negative values represent preventable cancer cases owing to protective effect.
- Table 4: Summary of cases and proportions of cancer in Alberta in 2012 attributable to use of oral contraceptives and hormone therapy*
Cancer site Oral contraceptive: ever use Hormone therapy: ever use Hormone therapy: current use Observed cases† Excess attributable cases‡ % Attributable§ Observed cases Excess attributable cases % Attributable Observed cases Excess attributable cases % Attributable Breast 2128 135 6.3 1665 258 15.5 1665 199 12.0 Endometrium 482 -276 -57.3 425 -48 -11.3 425 -23 -5.4 Ovary 179 -52 -29.1 143 13 8.9 143 12 8.4 All attributable cancers¶ 2128 135 6.3 1808 271 15.0 1808 211 11.7 All cancers** 7681 135 1.8 7681 271 3.5 7681 211 2.7 All preventable cancers†† 661 -328 -49.6 425 -48 -11.3 425 -23 -5.4 All cancers 7681 -328 -4.3 7681 -48 -0.6 7681 -23 -0.3 *Data on prevalence of oral contraceptive and hormone therapy use are from the Alberta's Tomorrow Project.
†Number of observed cancer cases in Alberta in 2012 at individual cancer sites. Cancer incidence data obtained from the Alberta Cancer Registry. For hormone therapy, only postmenopausal cancer cases (cancers diagnosed at age 53 yr and older) are included.
‡Number of cancer cases at individual cancer sites that can be attributed to oral contraceptive ever use, hormone therapy ever use or hormone therapy current use. Negative values represent preventable cancer cases owing to the protective effect of oral contraceptive ever use, hormone therapy ever use or hormone therapy current use.
§Proportion of cancers at individual cancer sites attributable to oral contraceptive ever use, hormone therapy ever use or hormone therapy current use. Calculated as excess attributable cases/observed cases.
¶Represents all cancers with a known association with oral contraceptive ever use, hormone therapy ever use or hormone therapy current use, as listed in table.
**Represents all incident cancers in Alberta in 2012 in all age groups.
††Represents all preventable cancer cases associated with oral contraceptive ever use, hormone therapy ever use or hormone therapy current use, as listed in table.