Researchers say China is repeating the United States' history of smoking

(CNN) -- Imagine a city the size of Chicago -- some 3 million people -- being wiped out in a single year.

A team of medical researchers from China and Britain says that alarming number of deaths is what China can expect in the next millennium -- from a single, preventable cause: cigarette smoking.

In the largest study of its kind ever done, researchers from Oxford University and the Chinese Academy of Preventative Medicine found that China is exhibiting the same kind of smoking pattern found 40 years ago in industrialized countries such as the United States.

Doctors say many Chinese adults believe smoking has little harm

If young men in China continue to smoke at the present rate, a third of them are destined to die prematurely from tobacco-related illnesses by 2040.

"It's a huge number of deaths," says Dr. Richard Peto from Oxford. "Half the smokers will get killed by smoking, and two-thirds (of young men) are smoking. It's a very big risk."

In 1990, the tobacco-related premature death rate in China was 13 percent, about what it was in the United States in 1950. By 2040, the study found, the death rate will be 33 percent, which was the rate in the United States in 1992.

There are other parallels. In 1952, the average number of cigarettes smoked in China was about 1 per adult per day, about the rate in the United States in 1910. That had risen to four per day by 1972, similar to what was seen in the United States in 1930.

By 1992, the Chinese smoking rate had risen to 10 per day, similar to the U.S. rate in 1950. Today, about one out of every three cigarettes smoked worldwide is smoked in China, close to 5 billion a day.

Long-term smoking magnifies the effects of existing disease, such as lung cancer

Among the Chinese population, most smokers are men. Few women have taken up the habit -- at least not yet.

"It's been the pattern throughout the world that men have started this and women have joined in later," says Dr. Jeffrey Koplan of the U.S. Centers for Disease Control and Prevention. "It just means that having smoked like men, they will die like men."

But even today, most Chinese still have no idea that smoking is dangerous. A 1996 survey found that two-thirds of Chinese adults believe smoking causes little or no harm, and 60 percent don't know smoking can cause cancer, according to Dr. Zheng-Ming Chen of the Chinese Academy of Preventative Medicine.

"Only about 10 years ago, people were saying, 'Oh well, smoking may kill Americans, it may kill British people, but it doesn't kill Chinese. It doesn't kill people in developing countries,'" says Peto.

Experts say that long-term smoking tends to magnify the effects of existing disease in a country. In China, where smoky air is common both indoors and outdoors, smoking has first increased deaths from obstructive lung disease, as well as lung cancer and even tuberculosis.

Adding to the already staggering disease burdens of the world's poorest countries, the study predicts that by 2030, nearly three out of four tobacco-related deaths will be in developing countries -- unless people there find out about the dangers now and quit smoking soon.