Smoking may affect human genetic material for more than 30 years

Smoking leaves its “footprint” on the human genome in the form of Deoxyribonucleic Acid (DNA)/genetic material methylation, a process by which cells control gene activity, according to new research in Circulation: Cardiovascular Genetics, an American Heart Association journal.

The new findings suggest that DNA methylation could be an important sign that reveals 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 Prof. Stephanie J. London, last author and deputy chief of the Epidemiology Branch at the National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina. “Equally important is our finding that even after someone stops smoking, we still see the effects of smoking on their DNA.”

Smoking remains the leading preventable cause of death worldwide, despite a decline in smoking in many countries as a result of smoking cessation campaigns and legislative action. Even decades after stopping, former smokers are at long-term risk of developing diseases including some cancers, chronic obstructive pulmonary disease, and stroke. While the molecular mechanisms responsible for these long-term effects remain poorly understood, previous studies linking DNA methylation sites to genes involved with coronary heart disease and pulmonary disease suggest it may play an important role.