Tobacco-related diseases may kill a third of middle-aged men by 2030 in China, where smoking habits resemble those of America in the 1950s, researchers found.

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Cigarette consumption in the world's most populous nation lags 40 years behind the US, where about 33 percent of adults aged 35 to 69 died of tobacco-related causes in 1990 as a result of heavy smoking in the 1950s, said Jacques Ferlay, of the International Agency for Research on Cancer. Ferlay told the Lancet Asia Medical Forum in Singapore on April 21 that he estimates the same death rate will apply to Chinese men by 2030.

China has 350 million smokers, equivalent to the population of Russia, Germany and Japan. Though cigarettes kill about a million people a year, doctors say the country may struggle to kick the habit because the tobacco industry contributes more than $30 billion to the government's annual revenue and helps support the economies of some of China's poorest provinces.

"Millions of people live on the income generated from the tobacco industry. You shut that down, you are asking for a riot," said Tony Mok, a professor clinical oncology at Hong Kong's Prince of Wales Hospital. "They have very little choice but to keep it going."

China National Tobacco Corp. made 2 trillion cigarettes last year, making it the world's largest cigarette producer. Some of the country's poorest provinces, Yunnan and Guizhou, rely on the industry for jobs and income.

'Smoke-Free' Olympics

About 57 percent of men and 3 percent of women aged 18 and over smoke in China, according to the World Health Organization's 2002 World Health Survey. Tobacco-related illnesses cost an estimated $5 billion in medical bills in 2000, according to a study published last year in the journal Tobacco Control.

There are signs China is moving to tackle the problem. In 2005, it became the 89th nation to ratify the World Health Organization's Framework Convention on Tobacco Control, the international treaty designed to reduce global demand for tobacco. And the government said that next year's Olympic Games in Beijing would be "smoke-free," banning tobacco in Olympic venues and on public transport.

"The great thing about China is that it is advancing so fast economically that weaning itself off tobacco should be easier than for India," said Richard Horton, editor-in-chief and publisher of the medical journal Lancet, which sponsored the two-day forum in Singapore.

Smoking caused about 500,000 new cases of lung cancer for men, and 200,000 for women in 2002, according to D. Maxwell Parkin, a visiting research fellow at the University of Oxford's clinical trials service unit. Doctors don't know how to account for the prevalence in women, who smoke less, though some believe it's caused by indoor smoke from coal stoves and cooking fumes combined with poor ventilation, according to Parkin.

The WHO estimates that 40 percent of all cancer worldwide could be prevented by avoiding tobacco, having a healthy diet, exercising, and preventing infections.

"Tobacco is the most important and preventable cause of cancer world-wide," said Ferlay of the International Agency for Research on Cancer. "There is a need to act now to limit the consequences of the tobacco epidemic."