Smokers who are seeking medical treatment to give up cigarettes are more highly addicted to nicotine than smokers who sought help two decades ago, U.S. researchers said on Tuesday.
The researchers examined nicotine dependence levels of about 600 smokers who entered treatment programs in northern California to quit smoking during three periods starting in 1989 and ending in 2006.
Seventy-three percent of those seeking medical help to quit smoking in 2005 to 2006 were deemed highly nicotine dependent using scores from a questionnaire given to assess the severity of nicotine addiction, the researchers said.
That compares to 55 percent of those seeking such help from 1989 to 1990 and 66 percent of those seeking treatment in 1994, Dr. David Sachs of the Palo Alto Center for Pulmonary Disease Prevention in California told a meeting of the American College of Chest Physicians.
Sachs said the findings suggest nicotine dependence is worsening among U.S. smokers as a whole, although researchers don't know why.
More nicotine in cigarettes
A report published by the Massachusetts Department of Public Health in 2006 found that levels of nicotine in most cigarettes rose by nearly 10 percent from 1998 to 2004.
Medical treatment to help people quit smoking may include nicotine replacement therapy such as a patch that delivers nicotine through the skin and into the bloodstream, nicotine gums, nasal sprays and inhalers, and antidepressant medication that raises the level of a brain chemical called dopamine.
The new study's findings are "important because what studies have consistently shown is that the more physically dependent a cigarette smoker is, the more intensive the treatment needs to be if the patient is going to be able to have a good treatment outcome and be able to stop smoking," Sachs said in a telephone interview.
"If you look at all of the cigarette smokers that we have around the United States, roughly three-fourths of them are going to be highly physically nicotine dependent," Sachs said.
An estimated 21 percent of U.S. adults — 45 million people — are smokers, including 24 percent of men and 18 percent of women, according to the U.S. Centers for Disease Control and Prevention.
The questionnaire, used to determine the degree of a person's of nicotine dependence, asked a smoker a number of questions such as whether they smoke their first cigarette within 30 minutes of waking up in the morning.
Other questions include whether they find it difficult to refrain from smoking in places where it is forbidden, how many cigarettes they smoke daily and whether they smoke even when they are so ill that they are bed-ridden.
