Menopausal Hormone Therapy and Dementia Risk
Association Between Menopausal Hormone Therapy and Risk of Dementia: Insights from a Nationwide Study
A recent nationwide, nested case-control study conducted in Denmark aimed to investigate the association between menopausal hormone therapy (MHT) and the development of dementia. The study utilized data from national registries and involved 5,589 incident cases of dementia and 55,890 age-matched controls, all of whom were Danish women aged 50-60 years in 2000 with no prior history of dementia or contraindications for MHT use.
The main objective was to assess the relationship between MHT use and dementia, considering factors such as the type of hormone treatment, duration of use, and age at usage. The study found that individuals who had received oestrogen-progestin therapy had an increased rate of all-cause dementia compared to those who had never used such treatment. The hazard ratio for all-cause dementia was 1.24 (95% confidence interval: 1.17 to 1.33) for those who received oestrogen-progestin therapy.
Furthermore, the study revealed that longer durations of MHT use were associated with higher hazard ratios for dementia, ranging from 1.21 (1.09 to 1.35) for one year or less of use to 1.74 (1.45 to 2.10) for over 12 years of use. Both continuous and cyclic regimens of oestrogen-progestin therapy showed a positive association with the development of dementia, with hazard ratios of 1.31 (1.18 to 1.46) and 1.24 (1.13 to 1.35) respectively.
Importantly, these associations persisted even among women who received MHT at the age of 55 years or younger. The findings were consistent when examining late-onset dementia and Alzheimer's disease specifically, with hazard ratios of 1.21 (1.12 to 1.30) and 1.22 (1.07 to 1.39) respectively.
This study provides evidence suggesting a positive association between menopausal hormone therapy and the development of all-cause dementia and Alzheimer's disease. The increased risk was observed regardless of whether continuous or cyclic regimens of oestrogen-progestin therapy were used, and even in women who initiated treatment at the age of 55 years or younger. Further research is needed to ascertain whether these findings represent a causal relationship between MHT and dementia risk or if they reflect underlying predispositions among women who require these treatments.