The 1964 U.S. Surgeon General report linking tobacco use with lung cancer and the ensuing tobacco control policies prevented nearly 800,000 lung cancer deaths from 1975 to2000, according to a new analysis by researchers at the National Cancer Institute.

Increased taxes, health-risk awareness, decreased advertising and label warnings prevented 795,000 of an expected 4 million deaths from tobacco-caused lung cancer if there had been no intervention, says Eric Feuer, who helped model the National Cancer Institute report.

Feuer's team used computer simulations to recreate the smoking histories of American smokers under three different scenarios: If smoking continued unabated, if tobacco ceased to exist after 1964 and under the real-world scenario where the government began imposing stricter regulations on tobacco after the surgeon general's report. America's tobacco control efforts prevented about 30 percent of the nearly 2.5 million lung cancer deaths that would have been prevented under the model where tobacco ceased to exist.

"The good news is that we've come a long way," Feuer says. "But we're not nearly done with what we need to do." Although the institute model only looked at lung cancer deaths, he says the health impact of tobacco control laws is surely much greater because smoking can cause a myriad of other health problems. "Lung cancer represents only a fraction of the total deaths associated with smoking and tobacco," he says.

In the early 1960s, more than 40 percent of Americans smoked. According to the National Institute of Health, that number is now below 20 percent.

An editorial published with the report says the models "give us a clear view to what should be the future of tobacco control in the United States."

David Levy, a professor at Georgetown University and an expert on tobacco control who co-authored the report, says the most important measures have happened in the last 15 years and have hit smokers where it hurts: their wallets.

The $206 billion settlement between four major tobacco companies and 46 states in 1998 probably did more than anything else to lower the number of smokers in the United States, he says.

"Right after the tobacco settlement in 1998, there was a 50 percent increase in cigarette prices," he says. "A lot of smokers quit. Since 2000, we've seen lots of states increase their taxes … You initially see a lot of people reducing the number of cigarettes they smoke, and then later they quit."

Many states have recently banned smoking indoors and in other public places, which can have a similar effect as raising prices, he says. Because ex-smokers generally don't see a significant reduction in their chances of getting lung cancer until after they've quit smoking for five years, America is just beginning to see the health benefits of those measures, he says.

Controversy has erupted recently over FDA plans to put graphic warnings on cigarette packs as early as September of this year. That plan hit a roadblock late last month as a federal judge blocked the effort, saying it infringed on tobacco companies' rights to free speech. The FDA says the warnings will help the U.S. lower the smoking rate to its goal of 12 percent by 2020. Levy says the graphic images would be a logical next step in combating tobacco use, adding that packages should include phone numbers to support lines that help smokers quit.

Levy says graphic warnings that target smokers of all ages has helped Brazil cut its smoking rate by half over the past 20 years. Despite the setback, he thinks the U.S. will eventually require companies to include the graphic warnings..

"They can have a big impact if they're geared towards people of different ages," he says. In Brazil, the warnings include images of coughing children, heart surgery, and dead bodies.