A quote from Plato’s work Phaedrus says, “Things are not always what they seem; the first appearance deceives many; the intelligence of a few perceives what has been carefully hidden.” This proverb is an apt description of some recent research on e-cigarettes and tobacco harm reduction, where first assumptions appear to be inaccurate based on a deeper examination of the data.
A recent 2019 article by Dharma Bhatta and Stanton Glantz in the American Journal of Preventive Medicine looked at the link between e-cigarette use and respiratory disease, using data from the USDA’s Population Assessment of Tobacco and Health (PATH) study. They concluded that e-cigarette use was an independent risk factor for respiratory illness, with statistically significant associations between these illnesses and current or former vaping use, and particularly with dual use of e-cigarettes and combustible tobacco products. According to Glantz, a well-known anti-tobacco activist, “This study contributes to the growing case that e-cigarettes have long-term adverse effects on health and are making the tobacco epidemic worse.”
However, more recent research from a team led by Cornell University professor Donald Kenkel found that using a more flexible empirical specification revealed a different set of outcomes. Using eight indicator variables and a 3 x 3 matrix of never, current and former users of combustible tobacco products versus never, current and former users of e-cigarettes, their study’s results found that:
- No evidence was found that current or former e-cigarette use is associated with respiratory disease
- Sole use of combustible tobacco and dual use with e-cigarettes have essentially the same statistical relationship with the onset of respiratory disease
Kenkel and colleagues analyzed the same data used In Bhatta and Glantz’s paper, closely replicating the results of the original analysis, but arriving at these more recent conclusions with the revised variables. Notably, the study’s 17,014 observations involved only 12 current e-cigarette users who had never smoked combustible tobacco. Their results have now been published in an NBER report, and also summarized in a recent VoxEU article.
In general, risk-factor epidemiology is shaping up as an important frontier in the harm reduction debate. For example, another 2019 study by Bhatta and Glantz that tied vaping to an increased risk of heart attacks was retracted earlier this year from the Journal of the American Heart Association, after subsequent research corrected for effects such as heart attacks occurring prior to the initiation of e-cigarette use. Examples such as these point to the importance of how data is used and analyzed for purposes of assessing the risk of tobacco harm reduction products.
The stakes for accurately assessing harm reduction product safety are very high, with hopes for a real impact on smoking cessation and public health hanging in the balance. While important questions remain in areas such as youth uptake and addiction, current science is showing that harm reduction products offer greater acceptance by current smokers and greatly reduced risk. Research such as this recent work at Cornell plays an important role in framing this debate going forward.
Bhatta, DN and Glantz SA (2019), “Association of E-Cigarette Use with Respiratory Disease Among Adults: A Longitudinal Analysis”, American Journal of Preventive Medicine 58(2): 182-190.
Kenkel DS, Mathios AD, Wang H (2020), E-Cigarettes and Respiratory Disease: A Replication, Extension, and Future Directions, National Bureau of Economic Research, NBER Working Paper 27507, http://www.nber.org/papers/w27507
Kenkel DS, Mathios AD, Wang H, “Research claims a link between e-cigarettes and respiratory disease: Not so fast,” VoxEU/CEPR, August 14, 2020. https://voxeu.org/article/research-claims-link-between-e-cigarettes-and-respiratory-disease-not-so-fast
McDonald, J, “Journal Retracts ‘Unreliable’ Glantz Study Tying Vaping to Heart Attacks,” Vaping360.com, February 20, 2020. https://vaping360.com/vape-news/88729/journal-retracts-unreliable-glantz-study-tying-vaping-to-heart-attacks/