May 22, 2012 -- A "smoking gun" gene may play a role in how many cigarettes certain smokers puff each day.
Researchers from 50 medical institutions across the country analyzed genetic material of more than 32,000 African-American smokers and non-smokers to see if certain genes predicted when they began smoking, how many cigarettes they smoked, and how easily they were able to quit.
According to the new study, a variant in a nicotine receptor gene predicts about one extra cigarette smoked per day. This same general location has been implicated in smoking behavior among white Europeans. Among African-Americans, the new genetic marker appears on a different spot on the same gene.
"This region is really important for addiction biology, regardless of race or ethnicity," says researcher Helena Furberg, PhD, an assistant attending epidemiologist at Memorial Sloan-Kettering Cancer Center in New York City.
This is somewhat surprising, she says. "Smoking behaviors differ among ethnic groups." For example, African-Americans typically start smoking at later ages than their counterparts of European descent and smoke fewer cigarettes each day. But they have a higher risk for lung cancer and are less likely to quit smoking.
The findings hold potential for tailoring smoking cessation treatments down the road, Furberg says. "The next research step would be to see if currently available smoking cessation medications would work better or differently among people who carry these variants."
Gene Predicts One More Cigarette per Day
Sean David, MD, is a clinical associate professor of medicine at the Stanford University School of Medicine in Stanford, Calif., and the lead researcher of the study. "Genes account for about 50% of differences between individuals in terms of risk for nicotine dependence and how many cigarettes they smoke per day," he says. This means environmental factors are equally important.
The new indicator predicts about one extra cigarette smoked per day.
David, director of the Translational Medicine Program at SRI International, hopes that these findings pave the way toward better smoking cessation treatments and prevention of lung cancer and other smoking-related diseases.
Anil Malhotra, MD, reviewed the new findings for WebMD. He is an investigator at the Feinstein Institute for Medical Research in Manhasset, N.Y.
"This genetic variant has a small effect on smoking behavior," he says. "The hope of all these kinds of studies is to identify at-risk individuals and/or help develop new therapies."
This takes time. "It is a lot of work from genetics to treatment, but this is a first step on a long path," he says. "Progress is being made in understanding the biology of these complex behavior syndromes."