Cannabis use among U.S. youths and young adults may be associated with an increased likelihood of progressing to regular tobacco use, according to findings from the PATH study.
In a propensity score matching analysis, investigators estimated that cannabis use accounted for about 13% of all new regular tobacco use in 2021—equivalent to approximately 509,800 additional youth and young adult tobacco users nationwide. Among adolescents aged 12 to 17 years who reported cannabis use at baseline in 2017, 32.7% became regular tobacco users by 2021, representing an absolute increase of 15.6 percentage points compared with matched controls. Among young adults aged 18 to 24 years, 14.0% of cannabis users progressed to regular tobacco use, a 5.4–percentage point increase over nonusers.
The longitudinal cohort study followed 13,851 participants aged 12 to 24 years who had never regularly used tobacco at baseline in 2017 and completed follow-up through 2021. Using propensity score matching, the investigators controlled for demographic variables, prior tobacco experimentation, perceived cigarette harmfulness, mental health symptoms, and household tobacco exposure. The participants who reported cannabis use in the prior 12 months were compared with nonusers matched on these characteristics.
Subgroup analyses highlighted the most pronounced associations among adolescents who had never previously used tobacco, for whom cannabis use increased the probability of regular tobacco use by 16.5 percentage points. Among young adults who had experimented with tobacco but weren't regular users, cannabis exposure increased the risk by 5.6 percentage points. No statistically significant effect was observed among young adults without prior tobacco exposure. Matching with replacement produced risk differences within 2 percentage points of the primary analysis, and weighted logistic regression yielded effect sizes and directions consistent with the matched results.
The study was funded by the Tobacco-Related Disease Research Program of the University of California and the National Cancer Institute. The authors reported no conflicts of interest.
“The finding that prior cannabis use is a major risk factor for initiation of current regular tobacco use among youths, independent of whether or not they have tried tobacco, suggests that cannabis prevention should be included as a key goal in tobacco control programs,” concluded Jiayu Chen, of the Division of Biostatistics at the Herbert Wertheim School of Public Health and Human Longevity Science as well as of the Moores Cancer Center at the University of California, San Diego, and colleagues.
Source: Tobacco Control
