(CNN) - It's been 50 years since experts spread the news that smoking kills. And since then making people aware of the dangers of cigarettes has helped save lives.
This weekend marks the 50th anniversary of the first surgeon general's report warning Americans of the dangers of smoking.
"The strongest relationship between cigarette smoking was in the field of lung cancer and probably a causal relationship between heart disease and cigarette smoking," Former Surgeon General Dr. Luther Terry said on Jan. 11 1964.
The American Medical Association estimates that since this announcement, decades of anti-smoking awareness campaigns, and laws have helped about eight million people extend their lives by an average of about 20 years, while 17.7 million deaths can be blamed on the habit in that time frame.
Health officials said 50 years ago, about 40 percent of the adults in America smoked. Now the numbers have dropped by more than half to about 19 percent.
But, experts said there is more work to be done.
"It remains the leading preventable cause of death in this country," Director of the CDC Dr. Thomas Frieden said.
And lung cancer isn't the only cancer threat. It can lead to others such as throat, stomach, kidney, bladder and more. And people who smoke are up to four times more likely to suffer a heart attack than nonsmokers.
Health officials say quitting is not out of reach.
"Most Americans who have ever smoked have quit and you can quit too," Frieden said.
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