The global prevalence of dementia: A systematic review and metaanalysis
Disclosures: Anders Wimo has been acting as consultant to drug companies (e.g., Pfizer, Janssen-Cilag, Astra-Zeneca, Novartis, Merz, Lundbeck, Forest, GSK, Wyeth, Sanofi, Elan, Neurochem, Lilly, BMS) purchasing or developing drugs for treatment of Alzheimer's disease or other dementias, but this has not influenced work associated with this study nor has there been any financing from these companies of this work. This systematic review was supported by a small grant from Alzheimer's Disease International (ADI) to King's College London. ADI has acknowledged support for the production and dissemination of the World Alzheimer Report 2009 from the Vradenburg Foundation, Geoffrey Beene Foundation, Alzheimer's Association, Alzheimer's Australia, Alzheimer's Australia WA, Alzheimer Scotland, Alzheimer's Society, Association Alzheimer Suisse, Alzheimerföreningen i Sverige, Deutsche Alzheimer Gesellschaft, and Stichting Alzheimer Nederland. The sponsors had no role in study design, data collection, data analysis, data interpretation, or the writing of this review.
Abstract
Background
The evidence base on the prevalence of dementia is expanding rapidly, particularly in countries with low and middle incomes. A reappraisal of global prevalence and numbers is due, given the significant implications for social and public policy and planning.
Methods
In this study we provide a systematic review of the global literature on the prevalence of dementia (1980–2009) and metaanalysis to estimate the prevalence and numbers of those affected, aged ≥60 years in 21 Global Burden of Disease regions.
Results
Age-standardized prevalence for those aged ≥60 years varied in a narrow band, 5%–7% in most world regions, with a higher prevalence in Latin America (8.5%), and a distinctively lower prevalence in the four sub-Saharan African regions (2%–4%). It was estimated that 35.6 million people lived with dementia worldwide in 2010, with numbers expected to almost double every 20 years, to 65.7 million in 2030 and 115.4 million in 2050. In 2010, 58% of all people with dementia lived in countries with low or middle incomes, with this proportion anticipated to rise to 63% in 2030 and 71% in 2050.
Conclusion
The detailed estimates in this study constitute the best current basis for policymaking, planning, and allocation of health and welfare resources in dementia care. The age-specific prevalence of dementia varies little between world regions, and may converge further. Future projections of numbers of people with dementia may be modified substantially by preventive interventions (lowering incidence), improvements in treatment and care (prolonging survival), and disease-modifying interventions (preventing or slowing progression). All countries need to commission nationally representative surveys that are repeated regularly to monitor trends.
