Bill Roberts has been a pack-a-day smoker for years.
And if the Chicago-based 30-year-old's lack of concern over the news that cigarette companies have been steadily raising nicotine levels in cigarettes is any indication, it is likely that he will continue his pack-a-day habit for many more years to come.
"Personally, this is not something that bothers me," Roberts says. "I am aware of the health risks of smoking. I do not believe that this is something that is good for me.
"Increased nicotine levels seem to come part and parcel with the compromises that you are willing to make to your health to smoke."
Roberts' nonchalance, though perhaps not shared by all smokers, may indicate one of the chief problems when it comes to tackling smoking as a public health issue.
And with the finding of increased nicotine levels in cigarettes, public health experts say that even those smokers who are willing to quit may have a harder time doing so.
However, the new study confirming that cigarette companies have been steadily increasing levels of addictive nicotine in its cigarettes could change the way the government deals with the tobacco industry.
And some public health experts suggest the findings may also lead the public into another round of litigation against cigarette companies.
The study by the Harvard School of Public Health, published in the current issue of the medical journal Lancet, shows that manufacturers increased nicotine levels in their products by close to 11 percent between 1997 and 2005.
"The cigarette is a reservoir, so the cigarette companies are increasing the potential of the smoker to extract nicotine," says Gregory Connolly, the lead author of the study.
The study's researchers say the findings are troubling with regard to both current smokers, for whom the nicotine increases could affect their addiction to cigarettes, and young smokers, who could get addicted to the more potent cigarettes more easily.
"The research has been done, showing that even just one exposure to nicotine triggers changes in the brain that put a child at risk of becoming a smoker," says Hillel Alpert, research analyst at the Harvard School of Public Health and an author of the study.
"Increased nicotine in a cigarette means an increased potential for it to change the brain."
"If you want kids not to become addicted to smoking, the levels should be going down, not increasing," Connolly says.
The study confirms the findings of previous research conducted by the Massachusetts Department of Public Health in August 2006 that suggested nicotine content in cigarettes was on the rise. The earlier study indicated a roughly 10 percent increase in nicotine levels in cigarettes from 1998 to 2004.
But now that a second study has confirmed the rise, many are asking whether the increase is deliberate or simply a fluke.
Carolina Group -- the tracking stock for the Newport, Kent and other tobacco brands owned by Lowes Corp. -- said "no comment" to ABC News' request for a response on the Harvard study. But at least one tobacco company has come forward to deny that increasing nicotine levels are deliberate.
"R.J. Reynolds does not have a program to systematically increase the nicotine content or smoke nicotine yields of its products," said Jeff Gentry, executive vice president of research and development for R.J. Reynolds, in a statement issued Thursday.
"Trends observed in the machine testing data may be due, in whole or in part, to the natural variability of tobacco crops from year to year, small errors in the machine-test method and/or changes in the range of brand styles available for smokers."
Researchers, however, say that the findings point to a deliberate effort by tobacco companies.
"Our research, based on industry-provided data, showed that this increasing trend is not random," Alpert says.
"This trend is real. It is increasing, and it is not attributable to chance."
Experts not affiliated with the study agree.
"The levels of nicotine in cigarette smoke are not an accident," says Stanton Glantz, professor of medicine at University of California at San Francisco. "Cigarettes are a heavily engineered product with a number of product controls. So, if there's an increase, it was not an accident."
"The tobacco companies do knowingly and purposely control nicotine levels in their cigarettes," says Michael Cummings of the division of cancer prevention and population sciences at Roswell Park Cancer Institute in Buffalo, N.Y.
"While one might expect slight year-to-year variations in nicotine levels, the consistent upward levels found seem to suggest this is purposeful. "
The idea that cigarette companies may be deliberately increasing nicotine levels in their products may serve as grounds for litigation and governmental regulation.
"The study emphasizes the need for FDA regulation of the cigarette industry and for current smokers to seek medical help of quitting this addiction," says Erika Schlachter, director of national advocacy for the American Lung Association.
"I think this kind of information could really stimulate or jump-start congressional efforts to give the Food and Drug Administration firm regulatory authority over tobacco products," says Peter Jacobson, director for the Center of Law, Ethics and Health at the University of Michigan School of Public Health.
"If this does not stimulate regulatory action or momentum for congressional action on providing FDA oversight of this industry, it's not clear what will," Jacobson says. "This is the exact reason and rationale for why you would regulate the product market."
Connolly agrees. "It's about time that we started making national policy decisions based on science and not solely on economic interests."
Jacobson, who believes "the chances are high" that litigation will also result from these findings, says the tobacco companies may be faced with an uphill battle when it comes to defending the increase in nicotine content in their products.
"It seems to me that this kind of action will potentially lead to product liability litigation or some type of class action deceptive marketing claim," he says. "The industry will have a difficult time explaining to a jury why it was OK to add additional nicotine after saying to the public how concerned it was with public health.
"There are some real inconsistencies here, the kind which often lead to large punitive awards."
Chicago smoker Roberts says that while he is hooked on cigarettes, he does not believe nicotine is the culprit behind his addiction.
"I don't think that increased nicotine levels are the reason why I continue to be a smoker," Roberts says. "Nicotine is a very small part of the reason I smoke. It is more the issue of social habits and other habits, and that the oral fixation aspect has much to do with it."
However, Connolly says many smokers may be more hooked on this addictive chemical than they realize.
"People smoke for nicotine whether they admit it or not," he says. "The basis of cigarettes is nicotine delivery; if you take it out, people won't smoke it."
Though the reasons why the tobacco industry might want to intentionally increase the nicotine levels in their products are not entirely clear, public health experts say an increased dose may lead to greater addiction potential.
In short, more nicotine may make it easier for new smokers to get addicted -- and more difficult for seasoned smokers to quit.
"It would appear that the companies are trying to compete by increasing the consumer acceptance of their products," says Dr. Joseph DiFranza, professor of family medicine and community health at the University of Massachusetts Medical School. "Cigarettes with higher nicotine yields are generally rated as more 'satisfying,' meaning that they satisfy the addiction."
"This is further evidence that manufacturers are seeking ways to make their products more addictive," says Dr. Jonathan Klein, at the University of Rochester. "It is particularly concerning for adolescent and young adult smokers, as they are more susceptible to addiction.
"Higher drug levels make continued addiction more likely."
Cummings says that whatever the motivation, the finding of the Harvard study suggests cigarette companies are moving in the wrong direction with regard to consumer health.
"The question that every consumer should be asking is why is the company saying that smoking causes disease and death and nicotine is addictive, but then putting more nicotine in cigarettes?" Cummings asks. "And what the hell is the government doing about it?"