Liz Szabo

USA TODAY

Declines in smoking have helped reduce deaths from cancer and heart disease

Anti-smoking efforts have been hailed as one of the great successes of public health

Yet nearly 18 million people have died because of tobacco in the past 50 years

Anti-tobacco efforts have saved 8 million lives in the 50 years since the publication of a landmark Surgeon General report, "Smoking and Health," a new analysis shows.

The 1964 report, which concluded that tobacco causes lung cancer, led to a sea change in American attitudes toward smoking. Smoking rates have plunged 59% since then, falling from 42% of adults in 1964 to 18% in 2012, according to the Centers for Disease Control and Prevention.

By avoiding tobacco or quitting the habit, people have gained nearly two decades of life, according to the analysis, published Tuesday in the Journal of the American Medical Association.

An American man's life expectancy at age 40 has increased by an average of nearly eight years, and a woman's by nearly 5½ years, since 1964. About one-third of those gains come from decreased tobacco use, the analysis says.

"Tobacco control has been described, accurately, as one of the great public health successes of the 20th century," CDC director Thomas Frieden writes in an accompanying editorial.

Twenty-six states and Washington, D.C., now ban smoking in indoor public places. As smoking rates have declined, so have the incidence rates of many cancers. About 40% of the decline in men's overall cancer death rates, in fact, is due to the drop in tobacco use, according to the American Cancer Society.

Tobacco damages virtually every part of the body, Frieden says, causing one-third of heart attacks. Smoking increases the risk of 14 kinds of cancer, including acute myeloid leukemia and tumors of the mouth, esophagus, stomach and pancreas, according to the American Cancer Society. About 443,000 Americans die from smoking-related illnesses every year.

Nearly 18 million Americans have died from tobacco just since the Surgeon General report was published, according to the new analysis, led by Theodore Holford of the Yale University School of Public Health.

Tobacco killed 100 million people worldwide in the 20th century, according to the Campaign for Tobacco-Free Kids. If current trends continue, tobacco will kill an additional 1 billion in the 21st century, the group estimates.

Frieden notes that smoking remains a major health challenge. Nearly one-third of non-smokers are still exposed to secondhand smoke, either at home or at work. Images of smoking are still common on TV and in movies. Tobacco taxes are too low in many parts of the country, making cigarettes affordable for both adults and kids. And although most smokers say they want to quit, few of them receive proven treatment, such as counseling and medication, which together can double their odds of kicking the habit, he writes.

A spokesman for R.J. Reynolds Tobacco Company declined to comment.

David Sylvia, a spokesman for Altria, the parent company of tobacco giant Philip Morris USA, says his company's goal today is simply to make current smokers aware of its brands, and it has no interest in attracting new smokers.

"Adults should have the ability to choose to purchase a legal product," Sylvia says. "We want to make sure that when adult, current smokers are choosing their brand, they think about our brand."