Nicotine-Cannabis Transitions and Nicotine Abstinence Among United States Adults.

Background: Prior studies examining the association of cannabis use with nicotine abstinence did not distinguish between individuals co-using nicotine and cannabis versus those who switched from nicotine to exclusive cannabis use; these may have different effects on nicotine abstinence. We examined associations of cannabis use uptake with subsequent nicotine abstinence approximately 1 year later among adults using cigarettes and/or e-cigarettes.

Methods: Using six waves of the Population Assessment of Tobacco and Health Study (2013-2021), we assessed transitions from exclusive nicotine use prebaseline (time t ) to (1) exclusive cannabis use, (2) nicotine-cannabis co-use, (3) nonuse of both nicotine and cannabis, and (4) continued exclusive nicotine use at baseline ( t + 1) as exposure variables. Analyses examined associations with nicotine abstinence (from both cigarettes and e-cigarettes) at 1-year follow-up ( t + 2).

Results: Among 8382 adults (19,618 observations) reporting exclusive nicotine use prebaseline, 1% transitioned to exclusive cannabis use, 9% to nicotine-cannabis co-use, and 9% to nonuse of both drugs; 81% were still using nicotine exclusively at baseline. Transition to nicotine-cannabis co-use (6%) versus exclusive nicotine use (10%) was inversely associated with nicotine abstinence at follow-up (adjusted relative risk [aRR] = 0.68; 95% confidence interval [CI] = 0.55, 0.83). Transition to exclusive cannabis use (72%) was positively associated with nicotine abstinence compared with continued exclusive nicotine use (10%; aRR = 4.66; 95% CI = 3.83, 5.67) and with similar nicotine abstinence at follow-up (72%) compared with nonuse of both drugs (65%; aRR=0.98; 95% CI = 0.81, 1.18).

Conclusion: Co-use of nicotine and cannabis was associated with lower nicotine abstinence. Switching to exclusive cannabis use was associated with similar or greater nicotine abstinence.