A rare and incurable endemic bone disease is posing a health risk to about 170,000 residents in a remote region in southwest China's Tibet, a medical survey has found.

At least 14,662 people have been diagnosed with Kaschin-Beck disease in eleven counties in Qamdo prefecture, one of the most seriously affected regions, according to the survey conducted by local health authorities. The patients usually develop thick and deformed joints, which eventually prevents them from working.

Doctors say the cause of the disease remains unknown. Some suspect that a certain fungus contained in barley, a staple food in the plateau, is to blame. Low iodine intake may be another cause.

The local government has been promoting relocation as a way to prevent the spread of the disease.

In the past five years, about 90 million yuan (or US$13.55 million) has been spent on the relocation program and nearly 20,000 residents have been moved out of the region.

(Xinhua News Agency October 18, 2010)