Smoking scars DNA in clear patterns, researchers reported Tuesday. Most of the damage fades over time, they found — but not all of it.
Their study of 16,000 people found that while most of the disease-causing genetic footprints left by smoking fade after five years if people quit, some appear to stay there forever.
The marks are made in a process called methylation, which is an alteration of DNA that can inactivate a gene or change how it functions — often causing cancer and other diseases.
“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.
Heart disease and cancer are both caused by genetic damage — some of it inherited, but most of it caused by day-to-day living. Smoking is one of the biggest culprits.
“The encouraging news is that once you stop smoking, the majority of DNA methylation signals return to never-smoker levels after five years, which means your body is trying to heal itself of the harmful impacts of tobacco smoking,” Joehanes said.