Building Evidence for Dementia Prevention

As was the case in 2010 when the National Institutes of Health issued a consensus statement on the prevention of Alzheimer’s and other dementias, there remains a lack of firm evidence for dementia prevention. Because of the difficulties in studying this phenomenon, no modifiable risk factors for dementia have been definitively established, and no pharmaceutical or nutritional supplements been proven to prevent Alzheimer’s disease or cognitive decline. However, longitudinal observational studies have identified several factors associated with dementia. A recent review article summarizes the current epidemiological evidence about Alzheimer’s and other dementias, and presents three ongoing large scale randomized control trials (RCTs) that focus on preventing dementia. The review argues that there is substantial evidence for many factors that, in combination, might reduce the risk of, or delay the onset of, dementia. Although no specific cure for dementia exists, and no specific pathway between risk factor and disease onset has been identified, several cardiovascular, stress, toxicity, and psychosocial variables have been repeatedly associated with dementia. Protective factors, such as high education, physical exercise, and not smoking cigarettes, have been identified as well. Intervention studies that account for these multiple factors may well identify strategies for preventing or delaying dementia. However, the protective effects and risk factors suggested by observational data have yet to be assessed in RCT research. The role of such factors in reducing or increasing the risk for dementia needs to be more specifically defined. Three ongoing RCT studies in Europe show promise in this area, as they target multiple risk and protective factors by promoting healthy lifestyle changes and medical treatment of vascular diseases. These are: FINGER, a Finnish trial involving 1,200 older adults at risk for dementia. This intervention features nutritional guidance, physical activity, cognitive and social engagement, and medical management of risk factors. Participants were involved in previous, intensive observational studies of vascular health and health behavior, so FINGER will provide a level of relevant information about its research subjects that is normally impossible for clinical RCTs to attain;MAPT, a multicenter study of 1,680 frail older adults in France. This study will compare the efficacy of omega-3 dietary supplementation with a multidomain training intervention that involves physical and cognitive training. The study will include follow-up assessments after five years;PreDIVA, a Dutch study of 3,534 community dwelling participants between 70 and 78 years old, recruited from primary care clinics. This study will compare standard medical care with a multicomponent vascular health intervention. The study will last for six years and measure both dementia and disability outcomes. These studies are an important step in dementia research, using earlier observational studies as the basis for rigorously assessed interventions. Although a cure for dementia has not been identified, this new research may identify preventive strategies against dementia. �� Source: Mangialasche F, Kivipelto M, et al. (2012). Dementia prevention: current epidemiological evidence and future perspective. Alzheimer’s Research and Therapy 4:6.