Precision hormone therapy: identification of positive responders.

Since the introduction of menopausal hormone therapy (MHT) in the 1940s, randomized clinical trials and observational studies have been performed to determine the benefits and risks of MHT. However, MHT therapeutic impact remains under debate as multiple factors including genetic biomarkers and medical history contribute to inter-individual variations in neurodegenerative diseases. Herein, we review the characteristics of women who participated in clinical studies and methodological approaches for study analyses to assess the critical variables influencing an association between MHT and risk of neurodegenerative diseases. Outcomes of the review indicated that: (1) observational studies assessed outcomes of MHT in symptomatic women whereas MHT clinical trials were conducted in asymptomatic postmenopausal women not treated for menopausal symptoms, (2) in asymptomatic postmenopausal women, late MHT intervention was of no benefit, (3) different MHT treatments and regimens between observational studies and clinical trials may impact outcomes, and (4) observational studies may provide greater predictive validity for long-term neurological health outcomes as MHT was introduced in symptomatic women and administered over a long period of time. Going forward, achieving precision hormone therapy will require a priori identification of symptomatic women appropriate for MHT and the type and dose of MHT appropriate for their genetic profile and health risks.