@hansens

I understand and share your concern. While there are no solid RCT data to assess absolute dementia risk for women starting transdermal estradiol + progesterone later in life, a recent large observational study published in Menopause (2024) provides some useful insight:
https://journals.lww.com/menopausejournal/fulltext/2024/05000/use_of_menopausal_hormone_therapy_beyond_age_65.3.aspx
This study examined various menopausal hormone therapy (MHT) formulations in women over 65 and found that transdermal estradiol combined with progesterone was not associated with an increased risk of dementia. Low-dose, non-oral formulations generally showed the most favorable outcomes (Table 4).

While this is observational data, not a randomized trial, it’s somewhat reassuring that this formulation did not show an increased signal for dementia.