NEW YORK - More than half of American men and over a third of women were smokers on January 11, 1964, when Dr. Luther Terry delivered the first Surgeon General's Report on Smoking and Health outlining the links between tobacco use, lung cancer and death.
Fifty years later, smoking rates have been cut by about half, and a new study estimates that 8 million Americans have been saved from premature smoking-related deaths.
"You look back in history to 1964, and in reality the world was a very different place when it came to tobacco use and smoking," said Rear Admiral Boris Lushniak, the acting US Surgeon General.
A collection of reports released online on Tuesday in the Journal of the American Medical Association (JAMA) highlights how public-health efforts, from cigarette taxes to advertising limits, have helped curtail smoking rates. The reports also identify new trouble spots, including communities whose members have not been able to quit in significant numbers.
Lushniak believes the next step should be a resolve to introduce an endgame within the next 50 years. That concept will be part of an upcoming Surgeon General's report on January 16 celebrating the anniversary of the original, he said.
"The next stage really needs to be a resolution to move ahead to this smoke-free generation concept," Lushniak said.
One paper estimates that about 17.7 million deaths from 1964 to 2012 were related to smoking.
Without any of the tobacco control measures introduced in that period, an additional 8 million people would have died, according to Theodore Holford of the Yale School of Public Health in New Haven, Connecticut, and colleagues.
The average American lifespan is also more than two years longer because those deaths have been averted, the researchers suggest.
Although Terry's 1964 report was not the first scientific review to connect cigarettes and health issues, it is widely considered a turning point in the battle against smoking.
"The announcement gave tremendous acceleration to the study of cigarettes and health," Dr. Otis Brawley, chief medical officer of the American Cancer Society in Atlanta, told Reuters Health.
Terry gathered 10 doctors, pathologists, chemists, statisticians and other experts to review the available evidence.
Because the tobacco industry in those days was so important to the US economy, Brawley said, the announcement was made on a Saturday to lessen any impact on the stock market.
The committee's conclusion was that smoking causes lung cancer in men and that men who smoke are more likely to die of heart disease than those who don't.
Based on research since then, the US Centers for Disease Control and Prevention (CDC) estimates there is a two- to four-fold increase in the risk of heart disease and stroke for smokers. The CDC also estimates that smoking increases the risk of lung cancer 13 times among women and 23 times among men.
The US is not alone in lowering smoking rates over the past few decades, another new study found.
Researchers from the University of Washington found that Canada, Mexico, Iceland and Norway cut the proportion of their populations that smoke by more than half from 1980 to 2012.
Worldwide, however, the slowdown is weaker, said Dr. Christopher Murray, one of the study's authors.
Data from 187 countries shows that about 41 per cent of men and 11 per cent of women worldwide smoked in 1980, and those rates have since declined to about 31 per cent for men and 6 per cent for women in 2012.
The actual number of smokers, however, rose from an estimated 721 million in 1980 to 967 million in 2012 as the world's population grew.
One approach to cutting the smoking rate involves targeting groups that are more likely to use tobacco.
People with mental illnesses, for example - including depression and anxiety disorders - had a slower decline in smoking rates, another report says.
Benjamin Cook, the report's lead author and a senior scientist at the Center for Multicultural Mental Health Research at the Cambridge Health Alliance in Massachusetts, and colleagues write that people with mental illness historically smoke at twice the rate of people without mental illnesses.
"If you were able to decrease those rates of smoking among people with mental illness, then you can really make a dent in national rates," he said.
The JAMA reports did not pinpoint what have been the most effective measures to induce people to quit smoking.
But public health advocates say the combination of tobacco taxes, smoke-free air laws, youth education campaigns and adequately funding state tobacco and anti-smoking programs has made a difference over time.
"I think we know what prevents people from continuing to smoke or not smoke at all," said Dr. Mariell Jessup, president of the American Heart Association.
Persistent efforts to keep children from smoking are also key, Brawley added.
"Very few smokers - less than 10 per cent - start smoking as adults," he said. "We really need to focus on keeping kids from smoking."
Brawley and Jessup said attention needs to be paid to electronic cigarettes - also known as e-cigarettes - which are electronic devices that deliver nicotine through vapour instead of tobacco smoke.
Previous studies have suggested that people can use the devices as smoking cessation tools, but some public health advocates worry that e-cigarettes may introduce more people to nicotine, the addicting chemical found in tobacco.
"E-cigarettes can be a very bad thing, can be a very good thing, and it can actually be both," Brawley said. "We need to figure that out."