Cigarette smoking has broad impact on human genome

The effects of cigarette smoking on DNA can last for years after smoking cessation, according to new research. In the meta-analysis, which involved pooled data from the CHARGE Consortium, many of the differentially methylated genes were novel with respect to the biologic effects of smoking.

The effects of cigarette smoking on DNA can last for years after smoking cessation, according to new research. In the meta-analysis, which involved pooled data from the CHARGE Consortium, many of the differentially methylated genes were novel with respect to the biologic effects of smoking. "We ended up finding a large signal, an order of magnitude more than any of the individual studies have seen," said Stephanie J. London, MD, DrPH, of the National Institute of Environmental Health Sciences in Research Triangle Park, NC. "We found changes in at least one site in about 7,000 genes, which is a lot." The study included data from about 16,000 people participating in the 16 CHARGE Consortium studies, including more than 2,400 current smokers, 6,500 former smokers, and nearly 7,000 never smokers. Within 5 years of smoking cessation, most of the DNA methylation sites studied returns to levels seen in never smokers; but some persisted for at least 3 decades after quitting smoking, the researchers said. The research—published in Circulation: Cardiovascular Genetics—was funded by grants from the National Heart, Lung and Blood Institute, the National Institute of Environmental Health Sciences, and the Intramural Research Program of the NIH.