Smoking scars DNA in clear patterns, researchers reported Tuesday.
Most of the damage fades over time, they found — but not all of it.
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.
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.
But smoking-related changes in 19 genes, including the TIAM2 gene linked to lymphoma, lasted 30 years, the team found.