Context:

There are conflicting data on postmenopausal hormone therapy (HT) and the risk of vascular dementia (VD) and Alzheimer’s disease (AD).

Objective:

We analyzed the mortality risk attributable to VD or AD in women with a history of HT use.

Design, Patients, Interventions, and Main Outcome Measures:

Finnish women (n = 489,105) using systemic HT in 1994 to 2009 were identified from the nationwide drug reimbursement register. Of these women, 581 died of VD and 1057 of AD from 1998 to 2009. Observed deaths in HT users with <5 or ≥5 years of exposure were compared with deaths that occurred in the age-standardized female population. Furthermore, we compared the VD or AD death risk of women who had started HT at <60 vs ≥60 years of age.

Results:

Risk of death from VD was reduced by 37% to 39% (<5 or ≥5 years of exposure) with the use of any systemic HT, and this reduction was not associated with the duration or type (estradiol only or estradiol-progestin combination) of HT. Risk of death from AD was not reduced with systemic HT use <5 years, but was slightly reduced (15%) if HT exposure exceeded 5 years. Age at systemic HT initiation (<60 vs ≥60 years) did not affect the death risk reductions.

Conclusion:

Estradiol-based HT use is associated with a reduced risk of death from both VD and AD, but the risk reduction is larger and appears sooner in VD than AD.