October 21, 2025

expert reaction to unpublished conference abstract looking at oestrogen therapy started during perimenopause (vs started after menopause vs not started at all) and risk of breast cancer, heart attack and stroke

A conference abstract presented at the 2025 Annual Meeting of The Menopause Society in Orlando looks at oestrogen therapy during perimenopause and the risk of breast cancer, heart attack and stroke. 

Prof Annice Mukherjee, Consultant Endocrinologist and Professor, Spire Manchester Hospital and Coventry University, said:

“Access to health insurance that includes menopause hormone therapy is likely to be limited to financially advantaged women, of higher socioeconomic status.  This may be a significant confounder in these results.  Many factors linked directly to socioeconomic advantage are likely to reduce post menopausal health risks.

“Healthy user bias is always difficult to unravel in Menopause research.”

Dr Rosie Cornish, Senior Research Fellow in Population Health Sciences at the Bristol Medical School, University of Bristol, said:

“The authors have concluded that “estrogen therapy initiated during perimenopause offers substantial protective benefits against breast cancer, heart attack and stroke…”.  However, the three groups being compared (those who started taking estrogen at least 10 years prior to menopause, menopausal women taking estrogen, and menopausal women not taking estrogen) may be different with respect to other risk factors for these outcomes that are not measured in the data.  As such, the apparent reduced risk for the group who initiated estrogen during perimenopause could be due (or partially due) to differences in these other factors.  Additionally, in order to be in the study, an individual would have needed to have survived and presumably not already had breast cancer, heart attack or stroke until at least the time of menopause.  If rates of these outcomes prior to menopause differ between those taking and not taking estrogen then this could potentially result in biased estimates of the differences between the groups.”

Abstract title: ‘The Timing of Estrogen Therapy: Perimenopausal Benefits and Postmenopausal Risks’ by Ify Chidi et al., being presented at the 2025 Annual Meeting of The Menopause Society in Orlando.  It was under embargo until 05:01 UK time on Tuesday 21 October 2025.

There is no paper.

Declared interests

Prof Annice Mukherjee: “Honoraria; Astellas, Novartis, Lilly. Research contract; Lilly.”

Dr Rosie Cornish: “No conflict of interest.”