Does Menopause Hormone Therapy Increase or Decrease Your Risk of Dementia?

Hormones and the Brain

A large body of pre-clinical research shows oestrogen helps protect the brain. It reduces any damage to nerve cells and supports overall brain health.

Receptors that respond to oestrogen are in areas of the brain related to reproductive functions. But they’re also in areas of the brain important for learning, memory and higher-order cognitive abilities such as planning, organisation and decision making.

Could Menopause Hormone Therapy Impact Dementia Risk?

Concern about dementia risk and menopause hormone therapy have been partially driven by the unexpected findings from a landmark study conducted more than two decades ago.

The findings showed hormone therapy use in post-menopausal women, 65 years and older, was associated with an increased risk for dementia. However, these studies have some key limitations:

1) most of the women were aged over 65 and more than ten years post-menopause

2) the type of oestrogen and progestogen used may have less benefit on brain health.

What Affects Your Risk?

It appears the effects of menopause hormone therapy on dementia risk are influenced by several factors. These include when someone starts taking it, how long they take it for, the type of hormones used, and the person’s genetic and health background.

1. When Therapy Starts: the Critical Window Hypothesis

One key factor in determining the effect of menopause hormone therapy on cognitive function and the risk of dementia appears to be when therapy starts relative to menopause. This is called the “critical window hypothesis”.

According to this hypothesis, oestrogen may help protect neurons in the brain only if started early in the menopause transition, particularly within a few years of menopause, when the brain may still be more responsive to hormones.

2. Type of Menopause Hormone Therapy and the Role of Progesterone

The type of hormones included in hormone therapy can vary widely in their molecular structure as well as their physiological actions.

Different types of oestrogens (such as estradiol or conjugated oestrogen) and the inclusion of a progestogen (needed for women who have not undergone a hysterectomy) may have different impacts on brain health and dementia risk.

Some studies suggest adding a progestogen to oestrogen therapy could counteract some of the cognitive benefits of oestrogen alone, possibly by blocking oestrogen receptors in the brain.

3. The Role of Vasomotor Symptoms

Vasomotor symptoms, such as hot flushes and night sweats, are the hallmark of menopause. Experiencing more vasomotor symptoms has been linked to poorer memory as well as an increase in biological markers associated with dementia risk.

Therefore, one possible pathway by which menopause hormone therapy may moderate Alzheimer’s disease risk is via their effects on reducing vasomotor symptoms.

4. A Person’s Genetic and Health Background

The greatest genetic risk factor for older-onset Alzheimer’s disease is carrying one or more copies of a specific version of the APOE gene, called APOE e4.

There is an emerging hypothesis that women who have this genetic risk for Alzheimer’s disease may show the greatest benefit from using hormone therapy.

What Does This Mean for You?

The clinical and scientific community are still debating whether menopause hormone therapy may play a role in Alzheimer’s disease risk.

Overall, the decision to use hormone therapy should be individualised, taking into account your age and timing of menopause, health status and specific menopause symptoms.

We need more research before we can make clear decisions about the role of hormone therapy and dementia risk, but based on the current evidence, hormone therapy may be beneficial if started early in the menopause transition, particularly for women at genetic risk of Alzheimer’s disease.

Conclusion

Menopause hormone therapy is a complex topic, and more research is needed to fully understand its effects on dementia risk. However, current evidence suggests that hormone therapy may be beneficial if started early in the menopause transition, particularly for women at genetic risk of Alzheimer’s disease.

FAQs

Q: What is the current understanding of the relationship between menopause hormone therapy and dementia risk?

A: The relationship between menopause hormone therapy and dementia risk is complex and influenced by several factors, including when therapy starts, how long it is taken, the type of hormones used, and the person’s genetic and health background.

Q: Can menopause hormone therapy reduce the risk of dementia?

A: The evidence is mixed, and more research is needed to fully understand the effects of hormone therapy on dementia risk. However, some studies suggest that hormone therapy may reduce the risk of dementia if started early in the menopause transition, particularly for women at genetic risk of Alzheimer’s disease.

Q: What are the potential risks and benefits of menopause hormone therapy?

A: The potential benefits of menopause hormone therapy include relief from menopausal symptoms, improved sleep, and potential protection against dementia. The potential risks include an increased risk of stroke, blood clots, and breast cancer.