Study Linked Vaping to Cancer-Related Cognitive Impairment. How Reliable are These Findings?

A study conducted by JCO Oncology Practice found a correlation between cancer-related cognitive impairment and vaping. But what does this correlation actually mean?

Study author Alexandre Chan, PharmD, MPH, FCCP, a professor in the department of clinical pharmacy practice and the division of hematology and oncology at the University of California, reported that survivors with cancer-related cognitive impairment had higher odds of vaping.

Chan and his team looked into a possible association between cancer-related cognitive impairment and substance use, including smoking, binge drinking, marijuana, prescription drug misuse and vaping.

The compiled data indicated that this kind of cognitive impairment was linked with 2.26 times higher odds of prior 30-day vaping. Chan theorized that this relationship could be blamed on the fact that as young adult survivors of childhood cancers face substantial challenges in coping with their cognitive and related complications, as well as mental health, hence they are more likely to self medicate in multiple ways, including vaping.

Correlation and causation are not the same thing
However the research team may have left out a crucial detail. Were the vapers included in the study former or current smokers? Did they turn to vaping in order to reduce the harm from smoking or to try quitting? Moreover, vaping was defined as any use in the prior 30 days, meaning that someone who had vaped even once in the prior 30 days, was being  considered in the same way as someone who vaped regularly multiple times a day.

Smoking cessation experts have long been highlighting that many vape studies are biased and therefore their findings are unreliable. In fact a group of international researchers under the leadership of CoEHAR, recently found that almost all of the 24 most frequently cited vaping studies published in reputable medical journals, are methodologically flawed.

Extensive bias found in vape studies
Mistakes and biases are known to be very common in e-cigarette research, resulting in misinformation and distortion of scientific truth. Led by Dr. Cother Hajat of the United Arab Emirates University and Prof. Riccardo Polosa, founder of the CoEHAR, a group of international researchers examined 24 vape studies which are peer reviewed and often quoted.

Titled, “Analysis of common methodological flaws in the highest cited e-cigarette epidemiology research,” the review asked what the most common flaws in e-cigarette research are and how to prevent them. Sadly, the findings indicated a plethora of fatal flaws in these studies, which the researchers identified, categorized, and accurately analyzed.

“Many studies lacked a clear hypothesis statement: to the extent that a hypothesis could be inferred, the methods were not tailored to address the question of interest. Moreover, main outcome measures were poorly identified, and data analysis was further complicated by failure to control for confounding factors,” reported the research team.

The flaws were particularly evident with regards to the Gateway Theory. “The body of literature on “gateway” theory for the initiation of smoking was particularly unreliable. Overall, the results and discussion contained numerous unreliable assertions due to poor methods, including data collection that lacked relevance, and assertions that were unfounded. Many researchers claimed to find a causal association while not supporting such findings with meaningful data: the discussions and conclusions of such studies were, therefore, misleading.” A press release by the review authors added that sadly, the most influential research on e-cigarette is not adequate to guide public health decisions.

Inaccurate studies are making their way into reputable journals
In line with this, the World Journal of Oncology Journal has recently retracted a 2022 article which claimed that vapers face the same cancer risk as cigarette smokers. Titled, “Cancer Prevalence in E-Cigarette Users: A Retrospective Cross-Sectional NHANES Study,” the study aimed to find the prevalence of cancer among vapers and smokers. The research team looked though data from the NHANES database to identify any associations and concluded that vapers were at a high risk for cancer. “In our study, e-cigarette users had an early age of cancer onset and higher risk of cancer.”

However, it was evident that the article reflected a broader pattern suggesting a peer review bias against vaping. To this effect, the journal editors highlighted that concerns were raised about the reliability of their findings, and given the authors failed to provide evidence-based explanations the article was retracted at the request of the Editor-in-Chief.

Sadly, the concerns raised by this retracted study are similar to ones found in many others. For instance, the study failed to specify whether the diagnoses were made before or after people started vaping. Any researcher would know that this is a minimum requirement for inferring causation. In fact, in 2020 a similar error led to the retraction of a study by infamous anti-vape advocate Dr. Stanton Glantz, linking vaping with heart attacks.

It is combustion, not nicotine consumption, that causes cancer in smokers
Meanwhile, two leading cancer experts recently reiterated said that it is the process of burning of tobacco not the consumption of nicotine, that causes cancer in smokers. “Nicotine does not cause cancer. Doctors even prescribe nicotine replacement therapy [NRT] to help smokers quit. Exposure to the carcinogens present in the smoke of combustible cigarette is what causes cancer. There is a dose-response relationship – the greater the exposure to a carcinogen, the higher the risk to develop cancer,” said Dr. David Khayat, a professor of Oncology at Pierre et Marie Curie University and head of Medical Oncology at La Pitié-Salpétrière Hospital, both in Paris.

Similarly, Dr. Peter Harper, a consultant medical oncologist at Guy’s and St. Thomas Hospital in London and chairman of the Toulouse Cancer Centre in France, said that the combustion process produces a set of toxic chemicals. “People smoke for nicotine but die from the burning of tobacco at over 350°C. The combustion of tobacco generates smoke and ash containing a toxic mix of chemicals that causes serious health effects, including fatal lung diseases and cancer.”

Dr. Harper is world acclaimed for his work which spans to over 400 papers and chapters in peer-reviewed publications. He has conducted research into developing improved forms of cancer treatment. Both Dr. Harper and Dr. Khayat extensively discuss and advocate the concept of tobacco harm reduction (THR), and the role that novel nicotine products may play in this.

The experts explained why novel products like heated tobacco products are a viable option. They highlighted that these products heat tobacco at a temperature of less than 350°C without combustion, hence deliver nicotine while producing 95% less harmful chemicals than cigarettes. Moreover, added Dr. Khayat, the fact that they are similar to cigarettes in that they require the so-called ‘smoking ritual’ where the smoker puts the “cigarette” it in their mouth, puffs on it, and so on, makes them more effective for smokers who are not only addicted to nicotine, but also to the action of smoking.