Smoking can impact DNA even 30 years after you quit

Smoking leaves its “footprint” on the human genes for more than 30 years, scientists have found, suggesting that people may be at risk of cancers, stroke and other diseases, even decades after kicking the butt.

The new study suggests that DNA methylation, a process by which cells control gene activity, could be an important sign that unveils an individual’s smoking history and could provide researchers with potential targets for new therapies.

“These results are important because methylation, as one of the mechanisms of the regulation of gene expression, affects what genes are turned on, which has implications for the development of smoking-related diseases,” said Stephanie J. London, from the US National Institute of Environmental Health Sciences of National Instit-utes of Health. “Equally important is our finding that even after someone stops smoking, we still see the effects of smoking on their DNA,” she said. The study appears in the journal Circulation: Cardiovas-cular Genetics.