Abbreviations AD: selleck chemicals llc Alzheimer’s disease; DHA: docosahexaenoic acid; MRI: magnetic resonance imaging; PFC: prefrontal cortex. Competing interests The authors declare that they have no competing interests. Acknowledgements We are grateful to DJ Lehmann (Oxford Project to Investigate Memory and Ageing (OPTIMA), Pharmacology Department, University of Oxford) for provision of the data in Table 1. MME has financial support from the National Institute for Health Research via the Oxford Biomedical Research Centre. SAC has financial support from Autism Speaks/Autistica. We acknowledge the very valuable and longstanding collaboration we have had with the staff of the Oxford Project to Investigate Memory and Ageing (OPTIMA).

Dementia is an acquired disabling syndrome characterized by progressive deterioration in multiple cognitive domains and is severe enough to interfere with daily functioning. Alzheimer’s disease (AD) is the most common cause of dementia, but increasing evidence from population-based neuropathological and neuroimaging studies shows that mixed brain pathologies (neurodegenerative and vascular) account for most dementia cases, especially in very old people [1,2]. Both prevalence and incidence of dementia rise exponentially with advancing age, and 70% of all dementia cases occur in people who are at least 75 years old [3]. The worldwide increase in the number of older adults, more pronounced in those who are at least 80 years old, explains the epidemic proportions assumed by dementia.

Because dementia is a major cause of disability in and institutionalization of older people, the increased prevalence of this syndrome places enormous pressures on health-care systems and society. The World Alzheimer Batimastat Report estimates that, in 2010, the number of people with dementia worldwide was inhibitor manufacture 35.6 million and that this will increase to 65.7 million by 2030 and 115.4 million by 2050 unless effective means of reducing the incidence of this disease are introduced [4]. In 2010, the total estimated worldwide costs of dementia were USD $604 billion, including the costs of informal care (unpaid care provided by family and others), direct costs of social care (provided by community care professionals and in residential home settings), and the direct costs of medical care (the costs of treating dementia and other conditions in primary and secondary care) [4]. No curative treatment is available, but epidemiological research provides substantial evidence of modifiable risk and protective factors that can be addressed to prevent or delay AD and dementia onset. In this review, we summarize the evidence supporting dementia/AD prevention and discuss key aspects that need to be considered when planning preventive strategies.