BACKGROUND AND PURPOSE:

• A link has been suggested between menopausal hormone therapy and increased risk of developing dementia, but evidence is lacking
• Vingradova et al. (BMJ, 2021) assessed the risks of developing dementia associated with different types and durations of menopausal hormone therapy

METHODS:

• Nested case-control study
  • Based on 2 large UK primary care databases
    • QResearch and CPRD GOLD
• Population
  • Cases: Women ≥55 with a primary diagnosis of dementia between 1998 and 2020
  • Controls: Matched by age, general practice, index date
• Exposures
  • Menopausal hormone therapy
• Study design
  • The association between dementia diagnoses and menopausal hormone treatments were quantified using odds ratios (OR)
  • Results adjusted for demographics, smoking status, alcohol consumption, comorbidities, family history, and other prescribed drugs
  • Dementia diagnoses derived from general practice, mortality, and hospital records 

RESULTS:

• Dementia diagnoses: 118,501 women | Controls: 497,416 women
• No difference was seen based on use of menopausal hormone therapy more than three years before the index date
  • In women with dementia: 14%
  • In controls: 14%
• There was a decreased risk of dementia among cases and controls <80 years who had been taking estrogen-only therapy for ≥10 years
  • Adjusted OR (aOR) 0.85 (95% CI, 0.76 to 0.94)
• Increased risks of developing specifically Alzheimer’s disease were found among women who had used estrogen-progestogen therapy for
  • Between five and nine years
    • aOR 1.11 (95% CI, 1.04 to 1.20)
    • 5 extra cases per 10,000-woman years
  • ≥10 years
    • aOR 1.19 (95% CI, 1.06 to 1.33)
    • 7 extra cases per 10,000-woman years

CONCLUSION:

• Overall, there were no increased risks of developing dementia associated with menopausal hormone therapy  
• There was a slightly increased risk of developing Alzheimer’s associated with long-term use of estrogen-progestogen therapy
• The authors state

These associations do not prove any causal link, but risks of breast cancer are also associated with longer term hormone therapy use, so the results are in line with existing concerns in guidelines about long term exposures to combined hormone therapy treatments 

Learn More – Primary Sources:

Use of menopausal hormone therapy and risk of dementia: nested case-control studies using QResearch and CPRD databases

BMJ Opinion: Menopausal hormone therapy and dementia

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