A U.S. study suggests the nicotine content of cigarettes has increased during recent years, making it tougher for smokers to quit.
Massachusetts Department of Public Health researchers found the amount of nicotine that could be inhaled from cigarettes -- even those labeled "light" -- increased 10 percent between 1998 and 2004, The Boston Globe reported Wednesday.
Nicotine, which can act as either a stimulant or relaxant, is the substance that causes cigarettes to be addictive.
Although the price of a pack of cigarettes has soared to as much as $5 in some areas, smoking rates still exceed 20 percent among U.S. adults.
"We in public health have tried to spend a lot of time figuring out why people don't stop smoking," Lois Keithly, director of the Massachusetts Tobacco Control Program, told the Globe. "It is more difficult to quit when there is a higher amount of nicotine in the cigarette."
The newspaper said representatives of the nation's three major cigarette manufacturers -- the Lorillard Tobacco Co., Philip Morris USA, and the R.J. Reynolds Tobacco Co. -- declined to comment on the study.
The research is said to be the first to track nicotine levels in seven years.
Copyright 2006 by United Press International
Explore further: E-cigarettes could be helpful for smoking cessation in hospitals