WNBA star Brittney Griner is in a Russian jail because the laws of the country you enter no matter what country you live in. A visitor to the US with banned substances is going to jail the same way. Yet to many Americans, what she had is no problem. She was not smuggling drugs, she had cannabis oil used for vaping.

In that, she is hardy alone. Much like medical marijuana prescriptions were overwhelmingly obtained by young men while pain prescriptions are overwhelmingly for older women, there is a clear demographic who take up vaping for the cannabis, not to quit smoking or reduce harm by replacing carcinogenic smoke with nicotine vapor.

Yet a new study uses statistics to try and suggest vaping leads to cannabis. And it claims something that is known not to be true, that there is an epidemic of vaping and it is increasing. 

The paper uses survey results which began in 2013 and is in a JAMA pay-to-publish journal, where peer review is often light editorial review. The Population Assessment of Tobacco and Health (PATH) study is a questionnaire, so already not in the world of science, but the authors parsed out 9,828 youths who reported that they had never used marijuana and found that between 2017 and 2019 young people who reported vaping were more likely to say they had also tried cannabis than youths who didn't say they had used any form of vaping at all.

The confounders are obvious. Youth is a time of experimentation and causal arrows for media while making sure to state it is only correlation in a young population is not evidence-based. The timeframes are also broad. If you do something once a month, that is not an epidemic. It is not even an addiction. 

The vaping company Juul is on the verge of collapse, so vaping was likely a fad for most, and its baseline will revert to those who want to quit smoking, or at least reduce harm, plus a contingent of marijuana users who desire a more culturally acceptable delivery mechanism. How large is that latter group? It's hard to know, but the authors say the majority of teens and young adults who have used e-cigarettes do it for cannabis rather than tobacco. That means vaping is not a gateway to drug use, drug users want more ways to use cannabis. Even then, a vapor will still be far less toxic than burning paper and leaves.