The chemical, cotinine, also stays longer in the bodies of women who have used alcohol for fewer years and have leaner body mass, according to the research.
Previous studies have noted consistent differences in cotinine levels between African-American and white smokers, with African-American smokers registering higher cotinine levels despite smoking fewer cigarettes per day. The new research suggests that factors beyond ethnicity, such as cigarette preference, may be behind this cotinine difference, say Karen L. Ahijevych, Ph.D., R.N. of Ohio State University and colleagues.
The study results are published in the December issue of Nicotine & Tobacco Research.
Ahijevych and colleagues examined cotinine levels in 32 African-American and white women who reported smoking an average of 20.4 cigarettes a day and had been smoking for an average of 15.3 years. The women were admitted to a research center for seven days, where their cotinine levels could be continually monitored. The researchers measured each woman’s cotinine levels after a typical day of smoking, and then measured the levels every eight hours during six days of smoking abstinence.
The amount of time it took for cotinine to clear out of the body varied among the women. Ahijevych and her co-authors determined that 52 percent of this variability could be explained by being an African-American menthol smoker, having fewer years of alcohol use and having greater lean body mass (body mass minus the mass of fat tissue). All three factors were associated with longer periods of cotinine existence in the body.
When the researchers examined cotinine levels in both African-American and white menthol smokers, significant differences in cotinine persistence between the two groups disappeared. This suggests that the menthol preference, rather than ethnic identity, may have been responsible for cotinine’s lingering effect in these women.
“A limitation of this study is that most African-American women smoked menthol cigarettes, while only one-third of Caucasian women did so,” Ahijevych and colleagues say.
The researchers also looked at differences in cotinine persistence between individuals and in individuals with a genetic variation implicated in cotinine metabolism, but the results of these comparisons were inconclusive.
Three of the women in the study had significant levels of cotinine even after refraining from smoking for more than five days. Ahijevych and colleagues suggest that at least seven days of smoking abstinence might be necessary to use cotinine levels as a reliable indicator of whether a person has stopped smoking.
This study was supported in part by the National Institute on Drug Abuse (NIDA), the Ohio State University General Clinical Research Center, the Ohio State University Academic Primary Care Program and the Bureau of Health Professions at the U.S. Department of Health and Human Services.
By Becky Ham
FOR MORE INFORMATION
Health Behavior News Service: (202) 387-2829 or www.hbns.org.
Interviews: Contact Dr. Karen Ahijevych at (614)-292-4699 or ahijevych1@osu.edu.
Nicotine & Tobacco Research: Contact Gary E. Swan, Ph.D., at (650) 859-5322.
Journal
Nicotine & Tobacco Research