Re-evaluation of large-scale hormone replacement therapy studies shows that HRT provides beneficial effects when initiated early in perimenopause or early menopause rather than later.
"they will conclude that there does appear to be a beneficial effect of certain hormone replacement therapies for perimenopause and menopause if the therapies are started early enough. Meaning if the therapies were started too late, there was some evidence of some detrimental effects perhaps. But if the therapies were started early enough, either in menopause or perimenopause, then there were some beneficial effects observed" (said at 1:13:38)
Re-evaluation of large randomized trials, notably the Women's Health Initiative (WHI), led to the 'timing hypothesis' (or 'window of opportunity' hypothesis) in menopausal hormone therapy. Subgroup analyses and subsequent trials demonstrated that when hormone therapy is initiated early (in perimenopause or within 10 years of menopause / before age 60), the risk-benefit balance is significantly more favorable (showing reductions in menopausal symptoms and fractures, with lower or neutral cardiovascular risks) compared to when therapy is initiated later in older women, where risks of adverse vascular events are increased. However, large randomized trials maintain that hormone therapy is not recommended strictly for primary disease prevention regardless of timing.
- context: The WHI ten year's later: an epidemiologist's view. (The Journal of steroid biochemistry and molecular biology 2014)
"In the ten years since the surprising early termination of those two WHI clinical trials, substantial discussion, critique, reanalysis, and opinion has been offered to reconcile the differences between the WHI clinical trial results and a diverse set of a priori and a posteriori expectations." (abstract, background, passage verified)
pubmedfull study (doi)