Misrepresentation of the risk of ovarian cancer among women using menopausal hormones
Misrepresentation of the risk of ovarian cancer among women using menopausal hormones. Spurious findings in a meta-analysis.
Based on a meta-analysis of 52 studies, and principally on a meta-analysis of 17 follow-up studies, it has been claimed that current-or-recent use (last use <5 years previously) of menopausal hormones causes ovarian cancer, even if the duration of use was <5 years, and that women aged about 50 years who use hormones for >5 years have about one extra case per 1000 users, and one extra fatal case per 1700 users.
To evaluate the validity of the evidence.
Generally accepted epidemiological principles of causation were applied to the evidence.
The study base included hysterectomised women, an unknown proportion of whom were oophorectomised, and not at risk for ovarian cancer. The findings did not satisfy the criteria of time order, bias, confounding, strength of association, dose-response, duration-response, consistency, and biological plausibility.
The meta-analysis did not establish that current-or-recent use of menopausal hormones causes ovarian cancer. The strong likelihood is that early symptoms of as yet undiagnosed ovarian cancer “caused” current-or-recent short-duration hormone use, not the reverse. The representation of the number of extra cases, and fatal cases, among hormone users was misleading and alarmist.
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