What do we mean by Alzheimer’s disease?BMJ 2010; 341 doi: http://dx.doi.org/10.1136/bmj.c4670 (Published 12 October 2010) Cite this as: BMJ 2010;341:c4670
- Marcus Richards, programme leader, Medical Research Council1,
- Carol Brayne, professor2
- 1MRC Unit for Lifelong Health and Ageing, London
- 2Institute of Public Health, University of Cambridge
- Accepted 25 July 2010
In the United Kingdom more than 700 000 people are estimated to have dementia. It costs the UK economy £23bn (€28bn; $35bn) per year1—more per patient than the median UK salary, and it is likely to become more prevalent as life expectancy increases. No effective treatments are available for most people with these disorders.
In 2009 the Department of Health National Dementia Strategy proposed several key objectives for relevant services in the UK, including improving public and professional awareness; achieving good quality early diagnosis and intervention; and developing and improving structured personal and peer support services.2 Alzheimer’s disease is the most common type of dementia. It is therefore important to look at what the diagnosis of Alzheimer’s disease represents, not least because the large volume of research on its pathophysiology has not led to any effective preventive breakthrough in the population, unlike cardiovascular disease and stroke. This article focuses on late onset Alzheimer’s disease that occurs after age 65 years—the most common expression of this syndrome—rather than early-onset Alzheimer’s disease, which is a comparatively rare, mostly autosomal dominant familial disease.
Challenges to the pathology-led view
Since the 19th century, when neuritic plaques and neurofibrillary tangles were identified as features of senile dementia, Alzheimer’s disease has been framed as a neuropathological entity—driven for example by amyloidosis or accumulation of oligomers and leading to neuronal death. Yet the diagnosis of Alzheimer’s disease in the living patients is made on the basis of clinical information that only rarely includes neuropathology. Suggestions have been made for the clinical formulation to take account of …