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: A total of 489,105 Finnish women using systemic HT in 1994-2009 were identified from the nationwide drug reimbursement register. Of these women, 581 died of VD and 1057 of AD in 1998-2009. The observed deaths in HT users with <5 or ≥5 years of exposure were compared with those having occurred in the age-standardized female population. Furthermore, we compared the VD or AD death risk of women who had started the use of HT at <60 versus ≥60 years of age.

RESULTS:

The risk of death caused by VD was reduced by 37-39% (<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. The risk of death caused by AD was not reduced with systemic HT <5 years of use, but was slightly reduced (15%) if the HT exposure had exceeded 5 years. The age at systemic HT initiation of <60 versus ≥60 years did not affect the death risk reductions.

CONCLUSION:

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