Researchers with the Chinese Medical Association say among men over 40, at least 40 percent experience male impotence, a sexual dysfunction characterised by the inability to develop or maintain an erection of the penis, the China Daily reported Monday.

About 83 percent of the sufferers in China "never sought medical treatment for the disease", said Wang Xiaofeng, director of the urology surgery department with Peking University People's Hospital.

Wang said poor public awareness and the underlying social stigma related to the disease are mainly to be blamed.

He made the remarks while making a report during the Fifth China Andrology Forum in Beijing over the weekend.

The released figures are based on surveys on erectile dysfunction carried out in 11 cities.
Men who reported being sometimes able or never able to get and keep an erection in the past three months were defined as suffering erectile dysfunction, Wang said.

For the majority of sufferers the cause was psychological, only 7.2 percent was caused by physical conditions. Some 30 percent suffered from both mental and physical causes, he said.

The research showed that lifestyle changes like more exercises and measures to prevent cardiovascular disease and diabetes, would help prevent erectile function. 

In a 2009 survey on people's sex life satisfaction, China ranked 11th among 13 Asian countries.