Study Links Cigarette Changes to Rising Lung Risk

While the nation's total lung cancer cases have inched down as the number of smokers has dropped in recent years, the study suggests an individual smoker's risk of getting cancer is higher.

It's well known that cigarettes differ from country to country, because of different tobacco crops grown locally and smokers' varying tastes. Nitrosamines are a byproduct of tobacco processing and levels vary for several reasons, including differences in curing practices.

Australian cigarettes contain about 20 percent of the nitrosamine content of U.S. cigarettes, making the chemical a prime suspect, concluded Burns, who has been scientific editor of several surgeon general reports on tobacco.

That doesn't rule out a role for deeper inhaling, cautioned Dr. Michael Thun of the American Cancer Society: "There's several strong suspects in the lineup. They may have acted in combination."

Philip Morris USA spokesman David Sutton called the study speculative and hard to evaluate until it's published in a medical journal, something Burns plans to do.

Still, Philip Morris, which supports FDA tobacco regulation, began taking steps with its growers in 2000 that have yielded "significantly lower" nitrosamine levels in recent years' supplies, Sutton said.

Be careful in assuming lower-nitrosamine cigarettes are less lethal, said Dr. Neal Benowitz of the University of California, San Francisco, a well-known tobacco expert. Lung cancer is only one of tobacco's many risks -- it causes heart disease and other killer diseases, too.

"If you reduce someone's (lung cancer) risk by 10 percent, that's not really meaningful for an individual," he said. "The goal still is to get them to stop."