Reacción a "Reactions: study associates hormone therapy for menopause with possible development of dementia "

This observational study reports on Danish registry data. The data suggest an association between the prescribing of combined oestrogen and progesterone preparations (mostly oral) and the diagnosis of dementia including Alzheimer’s. The age of starting hormone therapy was <55 years in 80% of the cases and the duration of use associated with all-cause dementia was 1 or more years or > 1 year for the subgroup of women with Alzheimers. There appears to be increasing likelihood of dementia with increasing years of use. No association was reported for oestrogen only (any route) or progesterone only use. 

The evidence to date has been concerning but also confusing. WHIMS study published randomised data in 2004 and reported an increase in dementia for women >65 years. Other randomised studies of selected populations did not report an increase. Recent observational studies also reported an increase for Alzheimer’s diagnoses only.   

The life time risk of dementia for women aged 65 is generally reported as 1 in 5. Women with symptoms, particularly hot flushes and sleep disturbance, need to consider the findings of this study and weigh up the benefits (symptom improvement) against the potential harms, which include the increased risk of developing dementia and Alzheimer’s. Women may choose to continue to use hormone therapy but limiting use to one year at the lowest dose that improves symptoms may be advisable. There is an adage that probably applies here - ‘the best medicine is the least medicine’. 

Further research could focus on use of oestrogen only and progesterone as this was not associated with an increased risk of dementia.