This is how business thrives: a Harvard study shows that tobacco companies have increased nicotine levels in cigarettes to keep smokers smoking.

Researchers from Harvard University have completed a report that studies data supplied by tobacco companies. It also expands on a Massachusetts Department of Public Health study issued in August 2006 which shows that the amount of nicotine that could be inhaled from cigarettes has increased an average of 10 per cent from 1998 to 2004.

The deliberate raise in nicotine levels is supposed to keep smokers smoking. Cigarettes apparently offer more puffs nowadays too, according to the analysis from the Harvard School of Public Health.

The researchers from Harvard corroborated the findings of the Massachusetts study and did a further examination, in an attempt to determine why cigarettes contain more nicotine.

"Industry says it's changed," said Greg Connolly, one of the authors of the Harvard study and former director of the state health agency's Tobacco Control Program. "Yeah, they've changed ???‚¬??? maybe for the worse."

Leading U.S. tobacco maker Philip Morris released a statement Wednesday night opposing the new study. The company argued that nicotine levels of its top-selling Marlboro cigarettes had fluctuated but that the rates in 1997 and 2006 were identical. The Harvard study, which was begun several months ago, did not include 2006 data.

What is perhaps ironical in this current situation is that the researchers from Harvard relied on information supplied by tobacco companies themselves. A 1996 state law required cigarette makers to test the nicotine that could be inhaled from their products, and Massachusetts ordered the use of machines that simulate a typical smoker's puffing.

According to Massachusetts regulations, cigarette companies are required to provide additional information to the Department of Public Health related to the delivery of nicotine, such as measures of nicotine concentration in tobacco, the number of puffs yielded by each cigarette, and the design of the filter.

Nicotine is one of the main ingredients in cigarettes that lead to dependence-forming, generating feelings of pleasure and relaxation. According to the American Heart Association, "Nicotine addiction has historically been one of the hardest addictions to break." It only takes about seven seconds for the substance to reach the brain.

The current Harvard study found that levels of inhalable nicotine during 1997 through 2004 increased in all types of cigarettes, menthol, full flavor, light or ultra light.

Their attempt to identify possible causes for the increase and concluded that the single most important factor in the heightened rates of inhalable nicotine was the amount of nicotine in the tobacco chosen for the cigarettes.

"It was systematic, it was pervasive, it involved all the manufacturers, and it was by design," said Dr. Howard Koh, an associate dean at the Harvard School of Public Health and an author of the study.

The study also said that the company data showed an increase in the number of puffs per cigarette, which the researchers said was probably due to a design change, but they could not determine the mechanism for that increase.

This means that you smoke not only because you want to, but because they want you to!

The Harvard researchers consider their study as overly sufficient evidence for federal government intervention: to regulate tobacco the way pharmaceuticals are controlled by the U.S. Food and Drug Administration.

"Cigarettes are finely-tuned drug delivery devices, designed to perpetuate a tobacco pandemic," said Koh. "Yet precise information about these products remains shrouded in secrecy, hidden from the public. Policy actions today requiring the tobacco industry to disclose critical information about nicotine and product design could protect the next generation from the tragedy of addiction."