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Dementia largest contributor to disability in elderly

27 November 2009

Dementia, rather than visual impairment and 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 from the Institute of Psychiatry at King's 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 expected to increase particularly rapidly in these regions, from 490 million to 1.6 billion between 2010 and 2050. 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 such as smoking, unhealthy diets and sedentariness are also becoming more common due to urbanisation, industrialisation, 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 in 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 per cent). Other substantial contributors were stroke (11.4 per cent), limb impairment (11 per cent), arthritis (10 per cent), depression (8 per cent), eyesight problems (7 per cent), and gastrointestinal impairments (7 per cent). 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.’

For full copy of the paper:



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