A new report by the World Health Organization expects dementia cases to triple worldwide by 2050.

Extended life expectancy and improved medical care in poorer countries are predicted to contribute to the increase.

Dementia is a brain illness that affects memory, behavior, and the ability to perform common tasks. Most dementia patients are cared for by relatives at an annual cost of $604 billion.

WHO Director-General Margaret Chan said the disease produces catastrophic costs that drive "millions of households below the poverty line."

Currently, 35.6 million people suffer from the disease. But the United Nations health agency expects that number to almost double by 2030 to 65.7 million. By 2050, it is expected to reach 115 million.

According to the report, only eight countries have national programs aimed at fighting dementia. It urged policy makers to address the problems of the disease as soon as possible.