In the first study to analyze the impact of genetic factors on multiple stages of tobacco use in both men and women, a team of researchers from Virginia Commonwealth University has found some of the strongest evidence yet for the role of genetic factors in smoking.
The multi-disciplinary team, from the Departments of Human Genetics and Psychiatry and VCU's Massey Cancer Center, analyzed data from personal interviews with 6,805 male and female adult twins registered with the Mid-Atlantic Twin Registry at VCU.
The team found that people differed in their risk to try cigarettes at least once. The analysis indicated that 75 percent of those differences were accounted for by genetic factors. Similarly, genetic factors contributed to 80 percent of the risk that someone would become a regular tobacco user, which was defined as using an average of at least seven cigarettes per week for a minimum of four weeks, and 62 percent of the risk that they would become dependent upon nicotine.
The study, published early online by Psychological Medicine, found no difference between men and women in the role of genetic factors in the liability to try smoking, become a regular user of tobacco or become addicted to nicotine.
"Although many people try smoking, it's been unclear why some people progress to regular tobacco use and then on to nicotine dependence," says Dr. Hermine H. Maes, assistant professor of human genetics, a researcher at the VCU Institute of Psychiatric and Behavioral Genetics and lead author on the article. The study will be published in a print issue of Psychological Medicine later this year.
"Different studies have implicated genetic components in smoking initiation," said Maes, who also is a member of the Cancer Control Program at VCU's Massey Cancer Center. "But now we also can quantify the contributions of genetic factors, as well as the contributions of such environmental factors as others smoking at home, specific to regular tobacco use and to nicotine dependence."
VCU has been a leader at looking at the causes and impact of tobacco use among children and adults through research at the Virginia Institute for Psychiatric and Behavioral Genetics and the Institute for Drug and Alcohol Studies.
VCU is the coordinator of the Virginia Youth Tobacco Project, a coalition of Virginia universities originated by the Virginia Tobacco Settlement Foundation to study why young people begin to smoke and why some become addicted to nicotine in tobacco products. The team, which also includes researchers from the University of Virginia, James Madison University, Virginia Tech, the College of William and Mary and George Mason University, also is evaluating which anti-tobacco programs work most effectively. The project is funded by the Virginia Tobacco Settlement Foundation, which was created by the General Assembly in 1999 to distribute part of the money Virginia will receive over 25 years from tobacco product manufacturers under a national Master Settlement Agreement with 47 states.
This study was supported by grants from the National Institutes of Health, the Virginia Tobacco Settlement Foundation and the Massey Cancer Center.