ArticlesCardiovascular and cancer morbidity and mortality and sudden cardiac death in postmenopausal women on oestrogen replacement therapy (ERT)
Introduction
Observational studies have shown a reduction in cardiovascular-disease risk and mortality in postmenopausal women on oestrogen replacement therapy (ERT), but to what extent this reduction results from selection bias is contested.1, 2, 3, 4, 5, 6 Weaknesses in the studies have been insufficient recording of cardiovascular disease, and lack of information on sudden cardiac death. The increased risk of endometrial cancer has been greatly decreased or almost eliminated by the addition of progestogen to ERT.7 However, opinions are still divided on the association between ERT and increased risk of breast cancer.8
The rapidly increasing use of ERT makes the question of its advantages and disadvantages highly pertinent. We report results from a community-based prospective cohort study. The study is based on questionnaires and repeated mammographies, and on the linking of existing registers in Finland. The registers contain information on individuals' health events during their lifespan.
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Study population and design
During 1987–88, all women born between 1923 and 1930 living in Turku were asked to participate in a free mammography screening for breast cancer organised by the city health authorities. Of 8164 invited, 7944 women participated in the study. A validated questionnaire was filled in by participants with the help of trained nurses who confirmed and checked answers. The questionnaire contained detailed inquiries about occupation, height, weight, smoking habits, and former and present use of hormone
Results
At baseline there was a significant difference between never users and current users of ERT in age (p<0·001), social class (p<0·001), BMI (p<0·001), hypertension (p<0·001), and diabetes (p<0·003); but not in smoking, CAD, or cardiac failure (table 1). Among current users, only endometrial cancer increased (p<0·001; table 2). Total mortality decreased among current users (p<0·001), as did stroke mortality (p=0·012) and other CAD deaths other than acute-myocardial-infarction (AMI) deaths
Discussion
As Grodstein5 points out, women who take hormones are a self-selected group and may have healthier lifestyles with fewer risk factors than women who do not. The occurrence of risk factors at the starting point of this study was different between current, former, and never users of oestrogen, but there was no significant difference between the groups in relation to smoking, occurrence of CAD, or cardiac failure. In some studies, women with CAD were excluded, as they were for instance, in the
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2010, Cancer Treatment ReviewsCitation Excerpt :In these patients, studied in the MA.17 trial, CVD in the LET group was not statistically different from that in the placebo group after 30 months of follow-up, and the incidence of MI was also similar (Table 2).12 The MI data are similar to what would be expected in an age-matched non-breast cancer population,70,71 and data from other databases, such as the UK General Practice Research Database or the Swedish MI register, also support this conclusion.72 Additional post-unblinding data from MA.17 have demonstrated a similar incidence of CVD in women electing to switch to LET after placebo and those continuing on placebo (4.2% vs 3.1%; p = 0.17); MI occurred in six and five patients in the respective groups.19