Is Hormone Replacement Therapy a Risk Factor or a Therapeutic Option for Alzheimer's Disease?

Alzheimer's disease disproportionately affects women, who comprise two thirds of all AD cases.

• AD accounts for more than half of all dementia cases in the elderly.
• Women comprise approximately two thirds of all AD cases.
• The underlying mechanisms for these sex differences are not fully elucidated.
• Evidence suggests a link between menopause and a higher risk of developing AD.

Decreased estrogen levels associated with menopause are implicated in AD pathogenesis.

• The review highlights the critical role of decreased estrogen levels in AD pathogenesis.
• Menopause is associated with a higher risk of developing AD.
• Estrogens have a clear role in modulating dementia risk.
• The review evaluated clinical and observational studies investigating the impact of estrogens on cognition in women.

HRT can have both a beneficial and a deleterious effect on dementia risk depending on multiple factors.

• The literature suggests that estrogens have a clear role in modulating dementia risk.
• Reliable evidence shows that HRT can have both a beneficial and a deleterious effect.
• Conflicting findings exist regarding HRT in the prevention and treatment of age-related cognitive deficits and AD.
• The review discusses mechanisms, effects, and hypotheses that contribute to the conflicting findings.

The age of HRT initiation is a critical factor in determining its effects on cognitive outcomes and AD risk.

• Recommendation for the use of HRT should consider the age of initiation.
• The timing of HRT initiation is identified as a key variable contributing to conflicting findings in the literature.
• Baseline characteristics such as genotype and cardiovascular health must also be considered alongside age of initiation.

Baseline characteristics including genotype and cardiovascular health modulate the effects of HRT on AD risk.

• Recommendation for HRT use should consider baseline characteristics such as genotype and cardiovascular health.
• Risk factors that modulate the effects of HRT require more thorough investigation.
• Dosage, formulation, and duration of treatment are additional variables that must be considered.
• These factors contribute to the conflicting findings across studies examining HRT and cognition.

The systematic review retrieved literature using databases OVID, SCOPUS, and PubMed with specific keywords related to HRT and cognition.

• Databases searched included OVID, SCOPUS, and PubMed.
• Keywords used were 'memory', 'dementia', 'cognition', 'Alzheimer's disease', 'estrogen', 'estradiol', 'hormone therapy', and 'hormone replacement therapy'.
• Reference sections from identified studies and review articles were also searched.
• The review focused on clinical and observational studies in women.