The Gateway Evidence, Reviewed: Does Vaping Lead to Smoking—or Do Smokers Just Vape?
The gateway hypothesis claims vaping causes smoking. The evidence: adolescents who vape are more likely to subsequently smoke. The confound: the same factors that predict vaping predict smoking. The gateway effect, if it exists, is small.
Adolescents who vape are more likely to subsequently smoke cigarettes. This is true. But the adolescents who vape are also more likely to have friends who smoke, parents who smoke, mental health conditions, and other risk factors for smoking. **When studies control for shared risk factors, the independent effect of vaping on smoking initiation is small—and at the population level, the countries with the highest youth vaping rates have the fastest-declining youth smoking rates. The gateway effect, if it exists, is small enough that it's overwhelmed by the broader trend of declining smoking.**
