On Jan.11,1964, Dr. Luther Terry, the U.S. surgeon general of the U.S. PublicHealth Service, released The Surgeon General's report of 1964, the first such analysis thatlaid out the effects of tobacco and smoking, and spurred initiatives to lower tobacco useamong Americans. Its conclusions were built on more than 7,000 studies on smoking andconcluded for the first time that smoking caused lung cancer in men, and likely in women,and that lighting up was the most likely cause of chronic bronchitis ( 慢性支气管炎) .
Now, fifty years later, thanks to Terry's efforts and those of his successors, astudy published in JAMA by researchers from the Cancer Intervention and SurveillanceModeling Network (CISNET) reports that 20% of adult Americans now smoke, comparedto 50% in 1964.
    In the latest study, the researchers looked at smoking patterns up to 1964 and thenestimated what the mortality rates would have been if no tobacco control strategies, suchas anti-smoking laws and higher taxes on cigarettes, had been implemented. Then, theycompared it to current smoking rates, and estimated that 157 million years of lives havebeen saved--about 19.6 more years for every smoker who quit.
    During the 50 years since the report, the researchers estimated that the lifeexpectancy for adults at age 40 increased 7.8 years for men and 5.4 years for women, andthat tobacco control efforts accounted for 2.3 of these additional years for men and 1.6 ofthem for women.
    Still, the researchers say, "Despite the success of tobacco control in reducingpremature deaths in the United States, smoking remains a significant public healthproblem." Another report, also published in JAMA, found that even though the percentageof the global population that smokes on a daily basis has decreased, the number ofsmokers has increased due to population growth. The new report showed that overallsmoking rates worldwide dropped by 42% among women and 25% among men. Rates inCanada, Mexico, Norway and Iceland dropped by more than half.
    Population growth, however, means that these rates are not making a significantdent in the absolute numbers of smokers around the world; since 1980, there are 41%more male smokers and 7% more female smokers.
Still, both reports highlight how effective tobacco control can be. "We know fromthese global trends that rapid progress is possible. If more countries were able to repeat thesuccess we have seen in Norway, Mexico, and the Unites States, we would see much lesshealth loss from smoking," said Emmanueta Gakidou, a professor of global health at theUniversity of Washington and author of the second study, in a statement.