BEIJING (Reuters) - A rare condition still haunts the poorest villagers on the Tibetan plateau but improvements in nutrition and grain handling could help eradicate it, the head of a Belgian group fighting Kashin-Beck disease said on Tuesday.

The poorest farmers tend to be most susceptible to the disease, which causes painful swelling in joints and retards limb growth, resulting in dwarfism in the most severe cases.

China’s Ministry of Health estimates about 2 million people have it, out of the 30 million who live in areas where it is endemic.

A multi-year study showed lower incidences in children who took multivitamin and mineral supplements, said Francoise Mathieu, director of programs for the Kashin-Beck Disease Foundation, which has been working in valleys around Lhasa where the disease is common.

“It’s been very encouraging and we hope to see more signs of improvement,” she told reporters in Beijing.

First identified by doctors stationed with Cossack units by Lake Baikal, Kashin-Beck disease was once found in an arc from Siberia, through northeast China and down into the southwest.

Advances in nutrition mean it has largely disappeared, except in remote valleys around Lhasa and elsewhere on the plateau.

Risk factors include lack of selenium and other nutrients in the diet, fungi that grow in grains and farming in mineral-poor soil.

In addition to the nutritional study, the foundation is encouraging farmers to treat seeds and store grains in clean, dry and ventilated rooms to avoid fungal growth.

“I think they live with much more suffering than we could,” said Philippe Goyens, a doctor who said severely deformed victims continue to farm and work in remote villages.

Better roads and more trade outside the valleys could help improve diets and reduce incidence of the disease, Mathieu said.

Last summer, the head of the Tibetan regional government said it had relocated 1,000 households affected by the disease, adding that people were only moved if they were willing, according to the Xinhua news agency.

Another 77,000 people in endemic areas in the Aba prefecture, in the high grasslands of Sichuan province, will be relocated by 2013, Xinhua said this spring, citing a local official.