June 24, 2009 – Despite recent declines in cigarette use in the U.S., nicotine dependence has remained steady among adults and has actually increased among some groups. The finding by researchers at Columbia University Mailman School of Public Health suggests that public health initiatives have been far more successful in preventing Americans from taking up smoking than in persuading hard-core smokers to stop. The study is available online in the American Journal of Public Health and will be published in the August 2009 issue.
Previous studies have found that since the 1964 U.S. Surgeon General report, the number of people who smoke cigarettes has declined. The Mailman School of Public Health study takes this research a step further by distinguishing occasional smokers from heavy smokers. "Regular, heavy cigarette use frequently characterizes nicotine dependence and is the pattern of use thought to be the most detrimental to health and longevity, but it has not been addressed in previous estimates of the decline in smoking prevalence," says Renee Goodwin, PhD, associate professor of Epidemiology at the Mailman School of Public Health and principal investigator of the study. "Rather, earlier research mainly addressed tobacco use or cigarette smoking per se rather than examining the frequency and duration of cigarette use in detail."
The new study finds not only that the number of nicotine-addicted Americans has held steady over the past several decades, but also that the proportion of cigarette smokers who are addicted to nicotine nowadays is greater than in previous generations. Dr. Goodwin cites a possible explanation for this latter finding. She suggests that fewer people are taking up smoking, perhaps because of anti-cigarette campaigns, leaving the ranks of current smokers filled with the nicotine dependent.
Another factor that has changed dramatically in the epidemiology of tobacco consumption and dependence over the past several decades is gender. Smoking has been far more common among men than among women for most of the past forty years, though recent evidence suggests that the gender gap has narrowed, and the current study finds increases in smoking among women in several recent generations.
It is also thought that socioeconomic status is a factor in cigarette use. The current study finds that younger women living in poverty had the highest rates of nicotine dependence, compared with older generations, and those not living in poverty. This suggests that despite increases in taxes and smoking costs, those most vulnerable are still heavily affected.
"Passage of this month's law governing the regulation of tobacco products and its focus on preventing smoking initiation among children is important and timely as our findings suggest that the number of people who still smoke is considerable," observes Dr. Goodwin. "Hopefully this legislation will help reduce the number addicted to nicotine in future generations since never smoking is the only sure way to prevent the development of nicotine dependence." "Given the mounting evidence that nicotine dependence plays a crucial role in smoking patterns, there is no question that future studies on curbing cigarette use need to take nicotine dependence into account," says Dr. Goodwin.