This is one of four evidence-based reviewsfrom the Minnesota Evidence-based Practice Center published in the Annals, which summarise findings from RCTs on the effectiveness of interventions to prevent cognitive decline, mild cognitive impairment, and clinical Alzheimer-type dementia.
An editorial notes that the lack of evidence reflects the challenge of studying prevention of a common chronic disease that originates well before symptoms occur. It suggests that to see effectiveness, trials on preventive interventions may need to begin when participants are in midlife, though such lengthy trials would have huge logistic challenges, be costly, and difficult to interpret because of probable selective attrition. It adds that equally challenging, is that many of the most promising interventions, such as controlling hypertension, avoiding smoking, exercising, and treating diabetes and other vascular risk factors, are already goals of standard medical care, thus the need for randomisation to control treatments would create ethical dilemmas. It concludes that there is no”magic bullet” to prevent Alzheimer disease and related dementias, though progress has been made recently in understanding the biology of the aging brain, and promising trials on dementia prevention are under way.