Most — but not all — DNA damage from smoking fades over time, and the genetic changes occur in clear patterns, researchers reported in an American Heart Association journal Tuesday, according to NBC News.
The researchers examined 16,000 people who'd given blood samples before, and found that most damage faded by about five years after a person quit smoking. But smoking-related changes in 19 genes lasted 30 years, and may persist forever.
"Our study has found compelling evidence that smoking has a long-lasting impact on our molecular machinery, an impact that can last more than 30 years," said Roby Joehanes, of Hebrew SeniorLife and Harvard Medical School.
The researchers said those 19 genes could be used to see who is at risk of smoking-related diseases or as targets for drugs to treat cigarette smoke damage.