This is the VOA Special English Development Report.

　　A new study says the leading cause of disability in older people in low and middle income countries is dementia. The researchers disagree with the World Health Organization which says blindness and other vision problems are the leading cause.

　　Dementia is a loss of intellectual ability that affects memory, learning, attention, thinking and language skills. People with dementia may forget family members or not know what day it is. Sometimes they become angry or sad, hear voices, or see things that are not there.

　　Renata Sousa from the Institute of Psychiatry at King's College London and other researchers wrote the new report. Their study looked at the causes of disability among fifteen thousand people age sixty-five or older in seven countries. The countries were China, India, Cuba, the Dominican Republic, Venezuela, Mexico and Peru.

　　The team found that dementia was the largest cause of disability in the elderly in areas other than rural India and Venezuela. Other major causes were stroke, loss of use of arms or legs, arthritis, depression, eyesight problems and gastrointestinal problems.

　　In low and middle income countries, heart disease and cancer get much of the attention given to chronic diseases. The researchers say increased importance should be given to chronic diseases of the brain and mind. As populations age, societies will have to deal with more and more cases of dementia.

　　The study says the elderly are nine percent of the total population of low and middle income countries today. But their numbers are growing quickly. They are expected to reach twenty percent of the total population by the middle of the century.

　　The study appeared in the Lancet medical journal which published a special issue on disability. A separate study of eighteen low and middle income countries dealt with children.

　　It found that in almost half the countries, children who were not breastfeed were much more likely to have a disability than those who were. The same was true of those who did not receive vitamin A supplements and those who were underweight.

　　Children who did not take part in early learning activities or attend school were also more likely to be disabled than those who did.

　　Researchers at the University of Wisconsin-Madison in the United States and UNICEF did the study.

　　And that's the VOA Special English Development Report, written by June Simms. I'm Steve Ember.