Alzheimer’s Disease and (Phyto) Estrogen Treatment: Modification of Effects by Age, Type of Treatment, and Duration of Use
Issue title: Therapeutic Trials in Alzheimer’s Disease: Where Are We Now?
Guest editors: Paula I. Moreira, Jesus Avila, Daniela Galimberti, Miguel A. Pappolla, Germán Plascencia-Villa, Aaron A. Sorensen, Xiongwei Zhu and George Perry
Affiliations:
School of Sports Exercise and Health Sciences, Loughborough University, Loughborough, UK
Correspondence:
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Correspondence to: Eef Hogervorst, School of Sports Exercise and Health Sciences, Loughborough University, Ashby Road, Loughborough LE11 3TU, UK. Tel.: +44 1509 223020; Fax: +44 1509 223940; E-mail: e.hogervorst@lboro.ac.uk.
Abstract: Background:There is a continued debate on whether menopausal hormone therapy (MHT) protects women against Alzheimer’s disease (AD). It is also unclear whether phytoestrogen could be an alternative treatment for AD. Objective:To investigate whether mixed study findings may be due to differences in age at initiation of MHT and duration of prescription of different types of MHT using meta-analyses. Methods:After a systematic literature search, meta-analyses were carried out using Cochrane Revman 5.4.1.software including data from large nationwide studies of registered medically diagnosed AD and prescribed MHT. These analyses were stratified for duration and type of treatment, by age at start of prescription of therapy. Insufficient quality data were available for phytoestrogen treatment and AD meta-analyses. Results:A total of 912,157 women were included from five registries, of whom 278,495 had developed AD during follow-up. Meta-analyses suggested a small increased AD risk after 5–10 years prescription of combination MHT regardless of age, and over 10 years only in women younger than 60 years of age. No association was seen for estrogen alone for women younger than 60 years of age, but AD risk did increase for women over 60 years of age for up to 5 years of MHT prescriptions. Conclusions:Combination MHT should probably be prescribed for less than 5 years after menopause to reduce risk for AD, while estrogen alone should not be prescribed to women over 60. For phytoestrogen, small treatment trials suggested some benefit of tempeh (fermented soy), which should be investigated further.
