Smoking's damage may be permanent

September 23, 1997|By DALLAS MORNING NEWS

DALLAS -- Cigarettes have a lasting legacy, even in smokers who haven't lit up for years, a new study of genetic damage suggests.

Scientists at the University of Texas Southwestern Medical Center at Dallas and other institutions have found that even though lung cells may appear healthy after someone stops smoking, harmful changes persist in their genetic material. The new study, scientists said, is one more reason to quit smoking or to never start.

"It's possible that even very modest amounts of smoking lead to damage," said Dr. Adi Gazdar, the leader of the UT Southwestern study.

Scientists believe that lung cancer occurs when disruptions, or mutations, accumulate in the genes that help control lung cells. When the genes are mutated, cells can divide out of control, form tumors and spread through the body.

Most lung cancers are attributed to smoking. And since the risk for cancer drops when people kick the habit, the Dallas researchers wanted to see whether genetic damage disappeared too. Gazdar said one theory has been that when someone stops smoking, their damaged lung cells are shed and healthy new ones take their place.

"We expected that, after a certain number of years, [genetic damage] would no longer be detectable," Gazdar said.

However, the researchers found similar amounts of genetic damage in lung cells from current smokers as in former smokers. Nonsmokers had no detectable damage.

The study results appear in the current issue of the Journal of the National Cancer Institute. Researchers from Baltimore; Santiago, Chile; and Vancouver, British Columbia, also participated.

Scientists from the University of Texas M.D. Anderson Cancer Center in Houston published a similar study in a June issue of the same journal.

It might seem that -- since genetic damage appears in former as well as current smokers -- quitting wouldn't make a difference. But that's not true, researchers said.

Dr. Li Mao, one of the M.D. Anderson researchers, noted that many studies show that stopping smoking does have benefits.

"The best advice is never start smoking," he said. "And if you smoke, you should quit smoking as soon as possible."

Pub Date: 9/23/97

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