The paper titled, “Evidence that an intervention weakens the relationship between adolescent electronic cigarette use and tobacco smoking: a 24-month prospective study,” concluded that “…e-cigarette use was robustly associated with measures of smoking over 24 months.”
Public Health expert Clive Bates explains why this study proved no such link and harm reduction advocate Carl V Phillips added that “it is yet another thought-free piece of public health garbage in which there is no hint of scientific thinking.”
Clive Bates explained that the researchers reported the following results:
“Baseline ever use of e-cigarettes was associated with:
ever smoked cigarettes (OR=4.03, 95% CI 3.33 to 4.88;
controlling for covariates, OR=2.78, 95% CI 2.20 to 3.51),
any recent tobacco smoking (OR=3.38, 95% CI 2.72 to 4.21);
controlling for covariates, OR=2.17, 95% CI 1.76 to 2.69)
and regularly smoked cigarettes (OR=3.60, 95% CI 2.35 to 5.51;
controlling for covariates, OR=1.27, 95% CI 1.17 to 1.39)
…at follow-up.”
He added that the claim that e-cigarettes act as a gateway is first mentioned here:
“The present research replicates previous findings in this area in showing a significant association between e-cigarette use and subsequent smoking initiation. It also shows similar effects for measures of regular smoking. These relationships were observed over a period of 24 months in measures of ever smoked cigarettes, any recent tobacco smoking and regularly smoked cigarettes. The strength of these associations was reduced but remained significant when controlling for various predictors of smoking..”
And reinforced in the following paragraph:
“These latter findings are more consistent with the view that e-cigarette use is a risk factor for smoking initiation than the view that e-cigarette use may simply be a marker for those who would go on to smoke cigarettes even without having tried e-cigarettes.”
Uncontrolled Confounding
“Note how sharply the association weakens when they control for the co-variates they have – e.g. from OR=3.60 to OR=1.27 – the observed effects are dominated by confounding”
Clive Bates points out that unless the various predictors of smoking which completely characterise the reasons why people smoke, are controlled for (which is impossible) any association may simply reflect uncontrolled confounding. “Note how sharply the association weakens when they control for the co-variates they have – e.g. from OR=3.60 to OR=1.27 – the observed effects are dominated by confounding. Who’s to say if they had more co-variates to better characterise predictors of smoking that the association would not disappear altogether,” he added.
On a post on his blog page, Carl V. Phillips explained Clive Bates’ arguments in depth. “Clive nails it there. If controlling for some half-assed deconfounder variables, which only roughly proxy for what you really want to be controlling for (in this case, propensity to use a tobacco product, whichever products are readily available), makes most of your association go away, then it is just nuts to think ‘and so whatever association remains is right.’ No, it obviously should be, ‘probably if we deconfounded this better, all of the association would disappear’.”
As vaping increases smoking decreases
Meanwhile, data released by the CDC in 2017, had indicated that as vaping has increased, smoking rates in high school students had been cut in half.
This CDC data had clearly indicated that smoking rates amongst high school students were cut in half in only five years, between 2011 to 2016. Most importantly during this same period, vaping amongst the same age group had increased from 1.5% to a peak of 16.0% in 2015, dispelling any theory that vaping acts as a gateway to smoking.
