Carcinogen reduction in a randomized controlled study comparing e-cigarette provision to assessment only among people with serious mental illness who smoke.

INTRODUCTION: Smoking rates among people with serious mental illness (SMI) are higher and quit rates are lower than in the general population. These individuals have higher levels of carcinogens in their bodies, contributing to greater prevalence of chronic disease and early mortality, necessitating implementation of novel harm reduction strategies, including switching to electronic nicotine delivery systems (ENDS). We conducted an RCT of ENDS provision versus assessment only in people with SMI who smoke to assess cancer risk reduction.

METHODS: 240 people with SMI (52 % male; 47 % schizophrenia, 53 % bipolar disorder; 55 % non-white; mean breath CO=26.9 ppm, sd=19.9 ppm) who tried but were currently unwilling to quit smoking were randomly assigned to receive disposable ENDS for 8 weeks or assessments only. Total urine NNAL (a metabolite of a tobacco-specific nitrosamine from smoke) was assessed at baseline, 4, and 8 weeks. Generalized linear mixed models examined the effects of ENDS provision on NNAL.

RESULTS: Mean NNAL did not differ by group at baseline (estimate=0.22; se=0.22; t = 0.98; p = 0.33). A significant group-by-time interaction (F=3.68, p < 0.026) indicated that NNAL decreased more over time in the ENDS group. The ENDS group had significantly lower NNAL at 4 weeks (estimate=0.54; se=0.23; t = 2.37; p < .02), but the difference attenuated at 8 weeks (estimate=0.42; se=0.23; t = 1.83; p < .07).

CONCLUSIONS: This study demonstrated short-term harm reduction among trial participants who received ENDS. Attenuation of the effect at 8 weeks suggests that ENDS provision alone is insufficient. Development of a program of behavioral support for ENDS substitution may help further reduce harm.