By Susan Farrer, NIDA NOTES Contributing Writer
Clove cigarettes, bidis, and additive-free cigarettes deliver at least as much nicotine as conventional cigarettes, suggests recent research conducted by NIDA Intramural Research Program (IRP) investigators in Baltimore. Smokers who choose these cigarettes are as likely to become addicted to nicotine as are other smokers and are exposing themselves to the increased risk of cancers, respiratory disease, and heart disease associated with smoking.
Bidi makers rolling tobacco into tendu leaves, a wrapping that has less porosity than that of conventional cigarettes and that lacks the filter ventilation holes seen in filtered brands. Despite having less nicotine, bidis deliver as much--or more--nicotine as conventional cigarettes.
Dr. Wallace Pickworth and his IRP colleagues conducted two studies comparing the effects of smoking clove cigarettes, bidis, and additive-free
cigarettes with the effects of smoking conventional filtered cigarettes as
part of an ongoing IRP program that examines nicotine delivery of alternative cigarettes. Their findings refute some consumers' belief that alternative tobacco products--sold on the Internet and at health food stores, ethnic groceries, and drug paraphernalia shops--are safer than conventional cigarettes.
Effects of Smoking Clove Cigarettes
In the clove cigarette study, the IRP investigators analyzed the physical composition of a particular clove cigarette brand and conventional
cigarettes and measured the nicotine, tar, and carbon monoxide (CO) delivery of the clove cigarette. They also conducted a small-sample clinical study comparing the nicotine delivery and physiologic and subjective effects of smoking clove cigarettes and conventional cigarettes.
In the nonclinical portion of the study, the investigators removed, weighed, and chemically analyzed the contents of 10 clove cigarettes and 10 each of 4 popular conventional cigarette brands. To measure how much nicotine, tar, and CO the clove cigarette delivered, they used machine-smoking methods based on those developed by the Federal Trade Commission. Analysis showed that the clove cigarette contained less nicotine and tobacco, but the smoking-machine analysis revealed that the clove product delivered more nicotine, tar, and CO than did the conventional cigarettes. The researchers attribute the clove cigarette's higher delivery of toxins to the lower porosity of its paper wrapper and its lack of filter ventilation holes, which are found on most ordinary cigarettes
and dilute the smoke inhaled with each puff.
In the clinical part of the study, 10 volunteers (7 men and 3 women) were asked to smoke a clove cigarette and a filtered conventional cigarette of their usual brand. The volunteers, whose mean age was 30.3 years, smoked an average of 21.3 cigarettes a day and had been smoking for an average of 13.4 years. Four of the volunteers had previously smoked clove cigarettes and all had smoked bidis in the past.
After the volunteers smoked the clove or conventional cigarette, the researchers measured their plasma nicotine levels, exhaled CO levels, blood pressure, and heart rates. They also recorded the time and number of puffs taken to smoke each cigarette, and the volunteers rated their satisfaction with smoking each cigarette and its sensory effects.
The researchers found comparable increases in the volunteers' plasma nicotine levels, exhaled CO levels, heart rates, and systolic blood pressure after smoking the clove and conventional cigarettes. However, the volunteers took longer and more frequent puffs of the clove cigarette than of their own cigarette brands (mean of 549 seconds and 15.1 puffs for the clove cigarette versus 314 seconds and 9.4 puffs for their own brands). This change in smoking behavior increases the amount of nicotine extracted from each cigarette, making it possible for smokers to achieve comparable blood concentrations of nicotine, even though clove cigarettes contain less of the drug per cigarette than do conventional brands.
Effects of Smoking Bidis and Additive-Free Cigarettes
In a related study, Dr. Pickworth and his colleagues compared the clinical effects of smoking bidis, additive-free cigarettes, and conventional
cigarettes. As in the clove cigarette study, this research involved 10 volunteers (9 men and 1 woman), all of whom had a history of smoking bidis. However, the volunteers' average age was younger (24.5 years) and they smoked more per day (25 cigarettes) than participants in the clove cigarette study, although they had smoked for fewer years (8.7 years).
In each of four separate sessions, each volunteer smoked a single
cigarette: an unfiltered, additive-free cigarette; a strawberry-flavored bidi; an unflavored bidi; and one of the subject's usual, filtered cigarettes. The researchers made the same analytical and physiological measurements and gathered the same behavioral information as they did in the clove cigarette study.
The analysis showed that 2 minutes after smoking, plasma nicotine levels increased the most for participants who had smoked the additive-free brand, followed by levels for smokers of the strawberry bidi, the unflavored bidi, and
the conventional cigarette. The volunteers' average heart rate also increased significantly for all of the cigarettes, with the greatest difference (8.5 beats per minute) seen after smoking the additive-free brand and the least difference (2.5 beats per minute) after smoking their own brand. The volunteers spent more time smoking the additive-free cigarette and unflavored bidi (mean of 453 seconds, and 354 seconds, respectively) than the strawberry bidi or their own brands (322 seconds and 297 seconds, respectively). They also took more puffs to smoke any of the bidis and additive-free cigarettes (approximately 14 puffs each) than to smoke their own brand (10 puffs).
Like clove cigarettes, the additive-free cigarette and bidis delivered more nicotine than did conventional cigarettes. Although both the flavored and unflavored bidis are smaller and contain less tobacco than conventional cigarettes, the bidis raised plasma nicotine to levels equal to or greater than the volunteers' own brands. The researchers theorize that like the thicker clove cigarette wrappers, the bidis' nonporous wrappers limit air dilution.
Not Safe Products
The NIDA scientists conclude that clove cigarettes, bidis, and additive-free cigarettes are not safe products and may be as harmful as conventional cigarettes. "Even though the bidis and the clove cigarettes have less nicotine in the cigarette rod--in the case of the bidis about one-third and in the case of the clove cigarettes about one-half or less--people are still able to extract about the same or even more nicotine than they would from a conventional cigarette," says Dr. Pickworth. "When individuals smoke these novel cigarettes, they adjust their cigarette smoking behavior to achieve plasma levels of nicotine comparable to those attained by smoking their own brands of cigarette. By that standard, they are at least equally dependence-producing. As a consequence, smokers will increase their smoking as dependence increases, exposing themselves to ever-greater smoking-related health risks."
Alternative Cigarettes and Young Smokers
Clove cigarettes, made in Indonesia and exported worldwide, are composed of 60 to 80 percent tobacco and 20 to 40 percent ground clove buds. They are usually machine rolled, are available with or without filters, and usually are sold in brightly colored packages. Clove cigarettes are sometimes referred to as "trainer cigarettes" and may serve as "gateway" products that introduce young people to smoking. The Monitoring the Future (MTF) survey, conducted by the University of Michigan's Institute for Social Research and funded by NIDA, tracks 8th-, 10th-, and 12th-graders' drug use, including use of tobacco products. In 2002, prevalence of clove cigarette smoking in the past year was 2.6 percent for 8th-graders, 4.9 percent for 10th-graders, and 8.4 percent for 12th-graders.
Bidis are small, brown, hand-rolled cigarettes that are made primarily in India and other South Asian countries. They are available in many flavors, such as chocolate, raspberry, and strawberry, making them appealing to adolescent smokers. The 2002 MTF survey reported that 2.7 percent of 8th-graders had smoked bidis in the past year; figures for 10th- and 12th-graders were 3.1 percent and 5.9 percent, respectively. In some geographic areas, rates are even higher. For example, a 1999 study by the Massachusetts Tobacco Control Program found that 16 percent of students in grades 7 through 12 in one large metropolitan area had smoked bidis in the 30 days prior to the study.
Additive-free cigarettes are made with whole-leaf tobacco and contain no chemical additives, preservatives, or reconstituted tobacco. IRP researchers report that many adolescents--and adults--believe that additive-free cigarettes are less harmful or less addictive than ordinary cigarettes, although scientific evidence contradicts that belief.
Malson, J.L.; Lee, E.M.; Moolchan, E.T.; and Pickworth, W.B. Nicotine delivery from smoking bidis and an additive-free cigarette. Nicotine and Tobacco Research 4(4):485-490, 2002.
Malson, J.L.; Lee, E.M.; Murty, R.; Moolchan, E.T.; and Pickworth, W.B. Clove cigarette smoking: Biochemical, physiological, and subjective effects. Pharmacology Biochemistry and Behavior 74(3):739-745, 2003.
Malson, J.L.; Sims, K.; Murty, R.; and Pickworth, W.B. Comparison of the nicotine content of tobacco used in bidis and conventional cigarettes. Tobacco Control 10(2):181-183, 2001.
Volume 18, Number 2 (August 2003)