Table 1 Description of included studies
Study | Study population | Age (mean) ±SD | Location | Group 1 | Group 2 | Type and route of estrogen | Follow-up (mean) in years | Outcomes |
|---|---|---|---|---|---|---|---|---|
Espie et al. [16] | 4949 postmenopausal women were included in two groups: exposed group, 2693 postmenopausal women who were receiving MHT or who stopped <5 years, and unexposed group, 2256 postmenopausal women who had never received MHT or who had stopped >5 years. MHT regimes were estradiol alone (351 postmenopausal women), estradiol + natural progesterone and estradiol + synthetic progestins (excluding medroxyprogesterone acetate and 19-nortestosterone derivatives) | 60.6 ± 6.3 for exposed group, 64.2 ± 8.3 for unexposed group | France | Estradiol + natural progesterone N1 = 999 | Estradiol + synthetic progestins (excluding medroxyprogesterone acetate and 19-nortestosterone derivatives) N2 = 1272 | Estradiol transdermal in 78 % and oral in 22 % | 2.5 | Breast cancer risk |
Fournier et al. 2008 [8] | 80,377 postmenopausal women were included in two groups: MHT never-users with 23,703 postmenopausal women and MHT ever-users with 56,674 postmenopausal women. MHT regimes were estrogen alone, estrogen + progesterone, estrogen + dydrogesterone, estrogen + other progestins, weak estrogens and other unknown MHT (almost exclusively estradiol compounds) | 55.0 ± 4.8 for MHT never-users, 52.3 ± 4.1 for MHT ever-users | France | Estrogen + progesterone (almost exclusively estradiol compounds) | Estrogen + synthetic progestins (almost exclusively estradiol compounds) | Postmenopausal women received either oral or transdermal estrogen (% not reported) | 8.1 | Breast cancer risk |
Cordina-Duverger et al. 2013 [17] | 1555 postmenopausal woman, 739 cases treated with combined estrogen and progestagen. 816 controls | Range (25–75) | France | Estrogen + progesterone: 25 cases and 34 controls | Estrogen + synthetic progestins : 55 cases and 43 controls | Not specified | 4 | Breast cancer risk |