According to a study published in a disability special issue of The Lancet, it is dementia and not blindness which is the biggest contributor to disability in older people in low and middle-income countries.

The conclusion is contradicting the global burden of disease estimated by the World Health Organization (WHO) which cites blindness as the biggest contributor to disability in this part of the population in developing countries.

Researcher Renata Sousa of the Institute of Psychiatry, King's College London along with her team from the 10/66 Dementia Research Group studied this area because disability in older people in these countries have not been involved in any research so far.

The numbers of older people are increasing fast in these areas along with a rise in the chronic diseases. This is done partly because of the process of demographic ageing and most of the chronic diseases occur more commonly in older people.

The authors concluded: "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.