Although previous research has suggested that the use of systemic hormone therapy may be protective against Alzheimer’s disease (AD), new findings in the BMJ suggest long-term exposure to hormone therapy may actually be associated with an increased risk.
Researchers examined data on hormone therapy use for 84,739 post-menopausal women in Finland who were diagnosed with AD between 1999 and 2013, and 84,739 matched controls without an AD diagnosis.
They found that overall the use of oral hormone therapy was associated with a 9 to 17 per cent increased risk for AD. The risk did not differ significantly between users of oestradiol only tablets and users of combined oestrogen-progestogen tablets, and the higher risk was not related to different progestogens. However, the exclusive use of vaginal oestradiol did not affect AD risk.
The authors noted age at which hormone therapy was started did not appear to affect future risk for the condition. However, in women who were younger than 60 years when they initiated hormone therapy, the increased risk was associated with exposure for over 10 years.
“Even though the absolute risk increase for Alzheimer’s disease is small, our data should be implemented into information for present and future users of hormone therapy,” the authors said.