Researchers claim that, prior to vaping becoming popular in 2014, the youth smoking decline was steadier and steeper. Consequently, they say, 1.66 million more youth started smoking than would have otherwise, "providing evidence...for the gateway effect."
Is it true?
[The TL/DR answer is No. If you want to know why we reject this claim, keep reading!]
First, they chose to compare 11 years (2002-13) to just 4 years (2014-19). They also chose to omit data from 2020 and 2021.
By averaging the yearly declines, they could say smoking declined by approx. 0.75% per year prior to 2014 to approx. 0.37% per year after 2014.
This makes it sound like youth smoking had a large steady decline before. But did it really?
No. Between 2006-10, well before vaping took off, there was also a 4 year stall. High school (HS) smoking only dropped 2.6 percentage points and between 2009-10 there was ZERO change.
The 2015-19 "slowdown" actually had a greater decline than the one in 2006-10, dropping by 3.5 percentage points.
So, by choosing to AVERAGE the annual declines over 11 years, researchers were able to "smooth over" that 2006-2010 stall, making the later one seem unique.
Interestingly, there was a total drop of 10.2 percentage points (from 22.9% to 12.7%) for HS smoking in that 11 years (2002-13) which averages to 0.93 percentage points per year.
If you look at 2006-10 it was an average of just 0.65 per year over 4 years.
But AFTER 2014...
Between 2015-19, HS smoking declined an average of just 0.875 percentage points per year, but that is still significantly better than the average 0.65 points per year between 2006-10.
But if you include the omitted 2020-21 data, the average decline is 1.23 points per year!
So, when we use ALL available data, HS smoking dropped more on average per year in the 6 years AFTER vaping became popular than it did in the 11 years prior.
But we're looking only at HS rates. Why did researchers choose to use combine both HS and middle school (MS) data?
The only reason we can see for that is to offset the dramatic change in HS smoking after 2013. You see, by 2013, MS smoking was already at a very low 2.9% so it only dropped to 2.3% by 2019 (still a good 20% decline.) HS smoking, on the other hand, dropped from 12.7% to 5.8%!
It's also a curious choice to combine HS rates with MS rates when you consider most of the dramatic vaping rates reported by the media are HS rates, which are far more relevant in predicting future young adult and adult smoking rates. (And MS smoking was down to just 1% by 2021!)
As HS smoking is a better predictor of future adult smoking, did all of the alleged "extra" 1.66 million teens who smoked in 2015-19 continue to smoke?
We can look at the young adult data for a hint....
In 2015, the HS vaping rate was 16%, and the young adult (18-24) smoking rate was 13%.
By 2021, those who were in high school between 2015-2019 were now all young adults and the smoking rate was DOWN by 56% to just 7.4%.
So, where are all of those "extra smokers" from vaping?
Researchers omitted important data (2020-21), "predicted" there should have been fewer teens smoking by pretending past slow decline periods weren't a thing, and ignored follow-up data (young adults.)
Did they prove there is a vaping "gateway effect?"
Not even close.