News Release

Dementia, not blindness, is overwhelmingly the most important contributor to disability in elderly people in low- and middle-income countries

Peer-Reviewed Publication

The Lancet_DELETED

Contrary to World Health Organization global burden of disease estimates, dementia, rather than visual impairment (including blindness), is the largest contributor to disability in elderly people in low- and middle-income countries. This is the conclusion of an Article published in this week's disability special issue of The Lancet, written by Renata M. Sousa, Institute of Psychiatry, King's College London, UK, and colleagues from the 10/66 Dementia Research Group.

Disability in older people in countries with low and middle incomes is little studied. Numbers of older people are increasing particularly rapidly in these regions, from 490 million to 1.6 billion between 2010 and 2050, or from 9% to 20% of the total population (compared with from 269 million to 416 million, or from 22% to 33% of the total population in high income countries). Chronic diseases are also on the rise, partly because of this process of demographic ageing - most chronic diseases occur more commonly in older people. However, chronic disease risk factors—eg, smoking, unhealthy diets, and lack of physical activity—are also becoming more common due to urbanisation, industrialisation, and dietary and behavioural change. Much of the focus on chronic diseases in countries with low and middle incomes has been on cardiovascular disease and cancer, conditions linked more to mortality rather than years lived with disability. In this study, the authors assessed the contribution of physical, mental, and cognitive chronic diseases to disability, and the extent to which sociodemographic and health characteristics account for geographical variation in disability.

The study looked at around 15,000 people aged 65 years or older in 11 sites is seven countries with low and middle incomes (China, India, Cuba, Dominican Republic, Venezuela, Mexico, and Peru), and worked out the proportion of disability that was due to each ailment, referred to as the population-attributable prevalence fraction (PAPF). The team found that in regions other than rural India and Venezuela, dementia made the largest contribution to disability (median PAPF 25%). Other substantial contributors were stroke (11.4%), limb impairment (11%), arthritis (10%), depression (8%), eyesight problems (7%), and gastrointestinal impairments (7%). Associations with chronic diseases accounted for around two-thirds of prevalent disability.

The authors conclude: "On the basis of empirical research, dementia, not blindness, is overwhelmingly the most important independent contributor to disability for elderly people in countries with low and middle incomes. Chronic diseases of the brain and mind deserve increased prioritisation. Besides disability, they lead to dependency and present stressful, complex, long-term challenges to carers. Societal costs are enormous."

In an accompanying Comment, Dr Steven R Sabat, Department of Psychology, Georgetown University, Washington, DC, USA, says: "There is a tidal wave of social problems on the horizon in the lives of people in developing countries, because the incidence of dementia is growing and will continue to grow."

He concludes: "The report from Sousa and colleagues...constitutes a call to action that cannot and should not be ignored."

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Renata Sousa, Institute of Psychiatry, King's College London, UK. T) +44 (0) 207 848 0177 / +44 (0) 7815 715 104 E) r.sousa@iop.kcl.ac.uk

Dr Steven R Sabat, Department of Psychology, Georgetown University, Washington, DC, USA. T) +1 (202) 687-3457 E) Sabats@georgetown.edu

For full Article and Comment, see: http://press.thelancet.com/dementialmic.pdf


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