Results

As shown in table 1, the 12 brands of bidi cigarettes had an average weight of 506 mg per cigarette. The tobacco weight averaged 215 mg. The tendu leaf wrapping accounted for 51.2–65.5% of the total cigarette weight. This supports prior findings that the tendu leaf is responsible for, on average, 60% of the total weight of a bidi.14 The nicotine concentration of the tobacco from the bidi cigarettes averaged 21.2 mg/g compared to the tobacco from filtered and unfiltered commercial cigarettes (table 2) that averaged 16.3 mg/g and 13.5 mg/g, respectively. Statistical comparisons of the nicotine concentrations revealed that the bidis contained tobacco significantly more concentrated in nicotine than the filtered (t(15) = 2.59, p = 0.02) and the unfiltered (t(13) = 3.87, p = 0.002) cigarettes. The weight of commercial filtered and unfiltered commercial cigarettes averaged 940 mg and 917 mg, respectively. The tobacco content of commercial filtered and unfiltered commercial cigarettes averaged 739 mg and 861 mg, respectively. Commercial cigarettes in the present study contained similar concentrations and amounts of nicotine to those reported in other studies.18 The overall average nicotine concentration of bidis (21.2 mg/g) was larger than any of the commercial brands of cigarettes (filtered or unfiltered). However, Irie Menthol bidis had an average nicotine concentration (15.5 mg/g) that was lower than American Spirit and several filtered commercial brands.

Discussion

The bidis tested contained less tobacco than other cigarettes. However, their tobacco contains significantly higher concentrations of nicotine than the tobacco of commercial cigarettes. One measure of the addictive potential of tobacco products is the amount of nicotine available to the consumer. Benowitz and Henningfield have theorised that a minimum threshold level of nicotine delivery is necessary to initiate and sustain dependence.15 Although cigarette manufacturers describe their products as “ultra lights,” “lights” and “full flavor” cigarettes, the nicotine content of the tobacco rods are similar.18 Cigarette smokers can titrate the amount of nicotine they obtain from a cigarette by changing their smoking behaviour.19 20 Smokers may titrate the amount of nicotine delivery from bidis just as they adjust the nicotine delivery from commercial cigarettes. However, preliminary results from a clinical study that measured plasma nicotine concentrations indicate that higher concentrations of nicotine were seen after smoking bidi cigarettes (Pickworth et al, 11th World Congress on Tobacco OR Health, abstract, 2000, unpublished data).

Bidi cigarettes are smoked differently than commercial cigarettes. For example, bidi cigarettes must be re-lit several times because they self-extinguish21 if they are not puffed at least two times a minute.14 The time to smoke and number of puffs were significantly greater while smoking a Sher bidi than commercial cigarette smoking in a clinical study (Malson and Stanton, Eastern Psychological Association, abstract, 2000, unpublished data). Finally, there is less air dilution through the tendu leaf than conventional cigarettes.7 Low combustibility forces a smoker to inhale more deeply resulting in greater delivery of carbon monoxide, nicotine, and other components of tobacco smoke.8 13 All of these factors may exaggerate the health risks associated with nicotine and other components of bidi smoke.

In addition to the well documented accounts of the toxic chemicals in bidi smoke, their delivery of nicotine poses a risk for the development of dependence. All smoked tobacco products have a potential abuse liability and the ability to initiate and sustain nicotine dependence.22 Even rapid delivery nicotine replacement products such as the gum and the nasal spray have a potential for abuse.23 The dependence potential of bidis is further evident in India where bidi smoking accounts for 40% of tobacco consumption.24

A recent study of urban US youth indicated that 40% had smoked bidis at least once and 16% were current users.6 There were no significant differences between race, ethnicity, and sex. “Better taste” was the reason most often endorsed for preference of bidis over commercial cigarettes.6 Highly flavoured smokeless tobacco products tend to appeal to a youthful market.25The flavouring additives may mask the harshness of the concentrated nicotine in the bidis and may allow for deeper inhalation while smoking. Teens are drawn to bidi cigarettes because they are highly flavoured and marketed as alternative products. Furthermore, teens are also attracted to bidi cigarettes because they are trendy, cheaper, and easier to buy than commercial cigarettes.5 6

Our interest in this research was to examine the nicotine concentrations of tobacco of several (12) popular brands of bidis. Because of the inherent variability in the production of a hand rolled tobacco product, another study could be conducted to determine the tobacco content and nicotine concentration within a single brand of bidi cigarettes. Other studies are needed to demonstrate the effect of bidi smoking on plasma concentrations of nicotine, exhaled carbon monoxide, and other physiologic effects.

In summary, results show that the nicotine concentration of the tobacco of bidi cigarettes is higher than the concentration of nicotine in commercial cigarettes. As a result of the nicotine exposure, bidi smokers are at risk for tobacco dependence. These findings refute the notion among US teens that bidi smoking is a safe alternative to commercial cigarettes.