Vaping-related deaths: analysis hints at THC as culprit

By Dr. Liji Thomas, MDOct 29 2019

The US Centers for Disease Control and Prevention (CDC) have now received information on 34 deaths and over 1,600 cases of e-cigarette, or vaping, product use associated lung injury (EVALI), as of October 22, 2019. This means over 120 new cases in just one week. The CDC has run a comprehensive analysis on 29 of the deaths.

The only common finding in all cases is a history of vaping or e-cigarette use. No single ingredient has been identified as the culprit so far, and some researchers think multiple substances could be incriminated.

Image Credit: FOTOGRIN / Shutterstock

Characteristics of death-associated cases

Of the 29 patients whose analysis is complete, almost 60% are men, with a median age of 45 years. In other words, the subgroup of patients who had severe EVALI leading to death is older on average than all EVALI patients in general. In fact, approximately 25% of deaths occurred in people older than 65 years, who comprised a mere 2% of the patients affected by the outbreak. The youngest patient to die, so far, was just 17 while the oldest was 75.

The CDC has data on substance use for only 19 of the dead patients. Among this subgroup, products containing tetrahydrocannabinol (THC) had been used at least once in 84%, those containing nicotine in 37%, while 63% and 16% used only products with THC and nicotine, respectively. THC is one of the major psychoactive substances in cannabis.

Substance use among EVALI patients

The same trends are seen when the data available for 867 patients, covering the 3-month period before the outbreak, is examined. 86% and 64% of patients had used products containing THC or nicotine, respectively, at least once in this period. 52%, which is over half of these patients, had used products containing both of them at least once. 34% and 11% used only products with THC and nicotine, respectively.

Among EVALI patients as a whole, young white males are dominant. Almost 80% are younger than 35 years, and the same number are non-Hispanic whites, while 70% are males.

When the age characteristics are further analyzed, approximately 50% of these patients are younger than 25 years, and 2 deaths have also occurred in this age group.

The sinister association with THC

Most of the analyzed samples do contain THC, and a history of vaping products containing THC has been obtained in approximately 85% of all cases. It seems likely that THC-containing products are connected in some way to the problem, especially when they have been bought by the streetside or from non-licensed individuals, including friends and family members as well as illicit vendors. However, the exact mechanism is in doubt – is the THC itself the harmful ingredient or is it just a characteristic of a certain manufacture process.

Secondly, most reports come from the patients themselves, which is generally recognized as a source of uncertainty – especially when THC is still not legal in some of the states from which EVALI has been reported. Thirdly, some of the patients could have well been unaware of the substances they were vaping. Finally, a variety of methods were used to collect data on substance use across different states. All of these could mean that the data is not completely trustworthy or is biased.

Implications: the warning

The CDC looks at the patient characteristics in order to build a picture of the outbreak and which group is likely to be affected by it. At present, there is no detailed explanation for why these deaths occurred.

The importance of the analysis is to help epidemiologists and clinical investigators to identify how and why this outbreak occurred. CDC director Robert R. Redfield says, “It is evident from today’s report that these lung injuries are disproportionately affecting young people. These new insights can help bring us a step closer to identifying the cause or causes of this outbreak.”

The CDC recommendations conclude: “We recommend that you do not use e-cigarette or vaping products that contain THC.  And since the specific cause or causes of lung injury are not yet known, the only way to assure that you are not at risk is to consider refraining from use of all e-cigarette and vaping products.  

Adults addicted to nicotine using e-cigarettes should weigh all risks and benefits, and consider utilizing FDA approved nicotine replacement therapies. They should not turn to or resume using combustible tobacco.  There is no safe tobacco product. All tobacco products, including e-cigarettes, carry a risk.”