This is one observational study. The Nurses Health Study (also observational) and the WHI clinical trials all showed increased stroke risk in estrogen users, regardless of age. Any attempts at reviving estrogen therapy as some sort of magical health tonic or preventative are falling on deaf ears. Women got the message and quit this poison and, thankfully, breast cancer rates across the globe dropped. There may have also been a decrease in ovarian cancers as well as first time heart attacks attributable to cessation (or never starting) estrogen, but that's not proven.