Exposure to Nicotine and Carcinogens among Southwestern Alaskan Native Cigarette Smokers and Smokeless Tobacco Users

Abstract

Background The prevalence of tobacco use, both cigarette smoking and smokeless, including iqmik (homemade smokeless tobacco prepared with dried tobacco leaves mixed with alkaline ash), and of tobacco-related cancer is high in Alaskan Native people (AN). To investigate possible mechanisms of increased cancer risk we studied levels of nicotine and tobacco-specific nitrosamines (TSNA) in tobacco products and biomarkers of tobacco toxicant exposure in Southwestern AN people. Methods Participants included 163 cigarette smokers, 76 commercial smokeless tobacco, 20 iqmik, 31 dual cigarette smokers and smokeless tobacco, and 110 nontobacco users. Tobacco use history, samples of tobacco products used, and blood and urine samples were collected. Results Nicotine concentrations were highest in cigarette tobacco and TSNAs highest in commercial smokeless tobacco products. The AN participants smoked on average 7.8 cigarettes per day. Nicotine exposure, assessed by several biomarker measures, was highest in iqmik users, and similar in smokeless tobacco and cigarette smokers. TSNA exposure was highest in smokeless tobacco users, and polycyclic aromatic hydrocarbon exposure was highest in cigarette smokers. Conclusions Despite smoking fewer cigarettes per day, AN cigarette smokers had similar daily intake of nicotine compared to the general U.S. population. Nicotine exposure was greatest from iqmik, likely related to its high pH due to preparation with ash, suggesting high addiction potential compared to other smokeless tobacco products. TSNA exposure was much higher with smokeless tobacco than other product use, possibly contributing to the high rates of oral cancer. Impact Our data contribute to an understanding of the high addiction risk of iqmik use and of the cancer-causing potential of various forms of tobacco use among AN people.

Fetal Exposure to Carcinogens With Tobacco Use in Pregnancy: Phase 1 MAW Study Findings

“…However, our results are consistent with a prior study by Benowitz et al, which revealed plasma cotinine and urine nicotine levels in AN men and (nonpregnant) women were significantly higher among iqmik users compared to cigarette and other ST users. 12 Plasma cotinine and urine nicotine levels were comparable between groups.…”

“…Cotinine, which has a longer half-life than nicotine, is a well-established biomarker for tobacco exposure and is easily measured in urine. 12 NNAL, the tobacco-specific carcinogenic metabolite of NNK, has an even longer half-life (10-16 days) and can also be measured in urine. 12,13,15 We sought to enroll a convenience sample of 165 pregnant women (55 smokers, 55 ST [commercial ST and iqmik] users, and 55 non-[tobacco] users) seeking prenatal care at SCF outpatient clinics.…”

“…In Phase 1, we aimed to establish the correlation between maternal tobacco use and fetal exposure to cancer-causing agents in pregnant AN women who use tobacco. We describe the methods, baseline participant characteristics, and urine biomarker results obtained from AN study participants in Phase 1 and summarize the relationships found between maternal urine cotinine (an established biomarker for nicotine use) and neonatal urine NNAL, or 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol, a metabolite of NNK, the potent tobacco-specific carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, 12,13 in AN women who used cigarettes or ST during pregnancy.…”

High tobacco use prevalence with significant regional and sex differences in smokeless tobacco use among Western Alaska Native people: the WATCH study

“…Nicotine and carcinogen bioavailability appear to vary dramatically across these tobacco products [49]. This study is limited to assessment of cigarettes, commercial ST and iqmik , mainly due to the minimal use of pipe or cigar smoking in these regions and by the collection of these baseline data well before the widespread use of e-cigarettes.…”

“…Research has demonstrated that dual- and multi-product tobacco users experience lower cessation rates [17,18], possibly due to greater cotinine and dependence levels [50]. On average, AN smokers living in Bristol Bay smoke about half as many cigarettes (7.8) per day [42] as US smokers (14.2) [51], but demonstrate similar plasma cotinine levels (170 ng/mL and 200 ng/mL, respectively), suggesting altered nicotine metabolism [49,52]. These changes in nicotine pharmacokinetics imply the need for a increased dosing of nicotine replacement therapy to aid in smoking cessation, a need that may extend to other AN populations, such as those in the Y-K or Norton Sound regions.…”