Kim Pulvers and colleagues recently published “Effect of Pod e-Cigarettes vs Cigarettes on Carcinogen Exposure Among African American and Latinx Smokers,” a well-done randomized controlled trial that demonstrated that African American and Latinx smokers who switched from cigarettes to Juul for 6 weeks had substantially lower levels of the lung carcinogen NNAL in their urine. (NNAL is one a a group of tobacco-specific nitrosamines that are created when tobacco is cured.) They found that NNAL levels were cut by about two-thirds and reported respiratory symptoms were cut by about one-third. There was no significant change in lung function, measured by the amount of air a person could blow out, or in blood pressure.
These results are not surprising because there is already a fairly well-developed literature in carcinogen exposure from e-cigarettes that shows users are exposed to lower levels of carcinogens than cigarette smokers are. This is likely due to the fact that there is no combustion which generates a lot of carcinogens and the fact that e-cigarettes run at lower temperatures than cigarettes.
In addition, fewer cancer-related genes in e-cigarette users are adversely affected than for cigarette smokers). This same study showed that while some of the adversely affected genes were the same for smokers and e-cigarette users, most were different. These findings suggest that the overall cancer risks for e-cigarettes are likely not just lower but different than for cigarettes.
In addition, the fact that e-cigarettes pose less cancer risk does not mean that there is no cancer risk. Indeed, scientists have already induced lung cancer in mice exposed to e-cigarette aerosol for 54 weeks.
In interpreting these findings, it is also important to keep in mind that cancer is “only” the cause of death for about one-third of smokers. Most of the rest are killed by heart and lung disease, where the e-cigarette risks are substantial.
Here is the abstract:
Question What is the effect of using nicotine salt pod system (NSPS) electronic cigarettes (e-cigarettes) for replacing cigarettes (ie, switching) on biomarkers of tobacco exposure and potential harm among cigarette smokers?
Findings In this randomized clinical trial including 186 African American and Latinx adult smokers, those randomized to the e-cigarette condition maintained their cotinine levels and significantly reduced urinary 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and carbon monoxide levels and respiratory symptoms compared with controls smoking as usual at week 6. Lung function and blood pressure remained unchanged.
Meaning This randomized clinical trial found that switching to NSPS e-cigarettes among adult smokers did not increase nicotine exposure and led to short-term reduction in the major pulmonary carcinogen, NNAL, compared with continued smoking. Abstract
Importance Fourth-generation nicotine salt pod system (NSPS) electronic cigarettes (e-cigarettes) are the leading class of e-cigarettes. They contain high nicotine concentrations, which may facilitate switching among smokers, but could also lead to increased exposure to nicotine and biomarkers of potential harm. African American and Latinx smokers experience significant tobacco-related health disparities. The potential of NSPS e-cigarettes to reduce smoking-related harm among these groups is unknown.
Objective To compare the harm reduction potential of NSPS e-cigarette vs combustible cigarettes.
Design, Setting, and Participants This unblinded randomized clinical trial compared 6 weeks of e-cigarette use vs cigarettes as usual from to 2018 to 2019 among smokers in the San Diego, California, and Kansas City, Missouri, areas. Participants included African American and Latinx adult combustible cigarette smokers who smoked at least 5 cigarettes/d on at least 25 of the past 30 days for at least 6 months and were interested in switching to e-cigarettes. Data were analyzed from September 18, 2019, to September 4, 2020.
Interventions 6 weeks of e-cigarette use in a choice of pod flavors (5% nicotine) along with brief education, training, and action planning to completely switch to e-cigarettes from combustible cigarettes. The control group smoked combustible cigarettes as usual.
Main Outcomes and Measures The primary outcome was reduction in urinary 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) concentration at week 6. Secondary outcomes were change in urinary cotinine, expired carbon monoxide (CO), respiratory symptoms, lung function, blood pressure, past 7-day consumption of combustible cigarettes, and switching rates (e-cigarette group only) at weeks 2 and 6.
Results This study included 186 participants, including 92 African American participants and 94 Latinx participants. The mean (SD) age was 43.3 (12.5) years, and 75 (40.3%) were women. Participants smoked a mean (SD) of 12.1 (7.2) cigarettes/d on 6.8 (0.6) d/wk at baseline. A total of 125 participants were randomized to the e-cigarette group and 61 were randomized to the control group. At baseline, median (interquartile range) NNAL was 124 (45-197) pg/mL in the e-cigarette group and 88 (58-197) pg/mL in the control group. At week 6, the e-cigarette group had significantly greater reductions in NNAL (relative risk [RR], 0.36 [95% CI, 0.23-0.54]; P < .001), CO (RR, 0.53 [95% CI, 0.42-0.68]; P < .001), respiratory symptoms (RR, 0.63 [95% CI, 0.47-0.85]; P = .002), and number of cigarettes smoked in the past 7 days among those still smoking (RR, 0.30 [95% CI, 0.20-0.43]; P < .001) than the control group and maintained their cotinine levels (RR, 0.80 [95% CI, 0.58-1.10]; P = .17). Lung function and diastolic and systolic blood pressure remained unchanged and did not differ between groups. For participants randomized to receive e-cigarettes, 32 participants (28.1%) were exclusively using e-cigarettes at week 6, while 66 participants (57.9%) were dual using and 16 participants (14%) resumed exclusively using cigarettes.
Conclusions and Relevance These findings suggest that e-cigarettes may be an inclusive harm reduction strategy for African American and Latinx smokers.
The full citation is Pulvers K, Nollen NL, Rice M, Schmid CH, Qu K, Benowitz NL, Ahluwalia JS. Effect of Pod e-Cigarettes vs Cigarettes on Carcinogen Exposure Among African American and Latinx Smokers: A Randomized Clinical Trial. JAMA Netw Open. 2020 Nov 2;3(11):e2026324. doi: 10.1001/jamanetworkopen.2020.26324. PMID: 33206193; PMCID: PMC7675102. It is available for free here.