Impact of nicotine reduction in cigarettes on smoking behavior and exposure: Are there differences by race/ethnicity, educational attainment, or gender?

Background: Lowering nicotine in cigarettes may reduce smoking prevalences; however, it is not known whether an immediate or gradual reduction in nicotine is the optimal approach for all population groups.
Objectives: We examined whether the optimal approach to nicotine reduction depended on the education, gender, or race of people who smoke and whether the optimal approach differentially benefited people who smoke based on their education, gender, or race.
Methods: Secondary analysis was conducted on a randomized clinical trial (N = 1250) comparing (1) immediate reduction from 15.5 to 0.4 mg of nicotine per gram of tobacco(mg/g);(2) gradual reduction to 0.4 mg/g;(3) control group with normal nicotine cigarettes(15.5 mg/g). Outcomes included cigarettes per day(CPD), carbon monoxide(CO), total nicotine equivalents(TNE), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol and its glucuronides(NNAL), phenanthrene tetraol(PheT), N-Acetyl-S-(2-cyanoethyl)-l-cysteine(CEMA). Data were analyzed as area under the curve(AUC).
Results: Results were presented by education (High school[HS] or less n = 505, more than HS n = 745), gender (males n = 701, females n = 549), and race (Black participants n = 373,White participants n = 758). Regardless of education, gender, and race, CPD, CO, TNE, NNAL, PheT, and CEMA were lower in immediate versus gradual nicotine reduction. Comparing immediate versus the control, outcomes were lower for all subgroups; however, the magnitude of the effect for TNE varied by race. Specifically, geometric mean of the AUC of TNE in immediate versus gradual was 49 % lower in Black participants and 61 % lower in White participants (p-value = 0.047).
Conclusions: Immediately reducing nicotine in cigarettes has the potential to benefit people who smoke across lower and higher educational attainment, male and female gender, and Black and White race.
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