(AP) — A new estimate says anti-smoking measures have saved roughly 8 million U.S. lives since a landmark 1964 report linking smoking and disease.

Yet the nation’s top disease detective says many other countries do a better job at trying to cut tobacco use.

The reports appear online Tuesday in the Journal of the American Medical Association. This week’s journal marks the 50th anniversary of a surgeon general report credited with raising health alarms about smoking.

More than 42 percent of U.S. adults smoked in years preceding the report; that rate has dropped to about 18 percent.

Smoking remains a stubborn problem and has been linked with heart disease, cancer, lung ailments and stroke. Those are the nation’s top four leading causes of death.