A study linking the use of nicotine vapes to liver disease has been retracted after its authors failed to reply to concerns raised about the article’s methods and findings.
Gastroenterology Research, a peer-reviewed journal, formally retracted the paper on June 11, stating in a short notice that “concerns have been raised regarding the article’s methodology, source data processing including statistical analysis, and reliability of conclusions.”
The retraction, which does not specify the nature of those concerns, came nearly a year after study’s publication, in June 2022.
The journal’s editor-in-chief, Robert Wong, also a clinical professor at the Stanford University School of Medicine, told Filter in an email that objections to the paper were raised in a letter to the editor. The study authors were given time to respond or prepare a rebuttal, he added, but they did not do so.
As such, the letter that prompted the retraction will remain under wraps.
Critics say the retraction is only the latest example of public health researchers overstating the harms of vaping in academic literature.
“As is our journal and publisher’s policy, because there was no response or rebuttal from the authors, the manuscript was retracted and the letter to the editor was not published,” Wong explained. “Typically, if there is an author response or rebuttal, we publish both the letter to the editor and the response.”
Critics, including advocates for tobacco harm reduction, say the retraction is only the latest example of public health researchers overstating the harms of vaping in academic literature.
“This is a greater problem than just one study,” Gregory Conley, director of legislative and external affairs for the American Vapor Manufacturers Association, told Filter. He pointed to the 2020 retraction by the Journal of the American Heart Association (JAHA) of a study connecting vaping to heart attacks.
Only about four in 10,000 scientific papers are retracted, according to a 2018 review.
In the 2020 case, critics’ letter to JAHA was made public, providing a measure of transparency into the retraction. What went wrong with the Gastroenterology Research paper is less clear, Conley said, because “there is silence around why it was retracted.”
The newly retracted study, titled “Association of Smoking and E-Cigarette in Chronic Liver Disease: An NHANES Study,” has 13 co-authors: Raja Chandra Chakinala, Sameer Dawoodi, Stephanie P. Fabara, Muhammad Asad, Azadeh Khayyat, Sangeetha Chandramohan, Aysha Aslam, Nkechi Unachukwu, Bibimariyam Nasyrlaeva, Richa Jaiswal, Sriram B. Chowdary, Preeti Malik, and Rizwan Rabbani.
Reached by email on July 12, Malik, the paper’s corresponding author and methodology contributor, told Filter, “Will get back to you on this by next week,” but did not provide further comment or respond to subsequent emails. Chakinala and Dawoodi, who headed the study’s conceptualization, also did not respond to emails by publication time.
To conduct their research, the authors drew from a publicly available database, the National Health and Nutrition Examination Survey (NHANES), and analyzed participants’ responses, looking for associations between liver disease and the use of cigarettes or vaping products.
The results, they claimed, showed that “e-cigarette users … were associated with higher odds of having liver disease compared to non-smokers.”
“I already have a bunch of questions just off the top of my head, basically, just looking at this paper.”
While we don’t know what specific concerns led to the study’s retraction, one public health expert said some flaws in the methodology should have been obvious.
Ray Niaura is a psychologist and epidemiology professor at New York University’s School of Global Public Health who studies tobacco dependence and treatment. “I already have a bunch of questions just off the top of my head, basically, just looking at this paper,” he told Filter.
One shortcoming, he said, is with the NHANES data itself. The only survey question on vaping is extremely broad, asking: “Have you ever used an e-cigarette?” By comparison, questions involving combustible tobacco include “Do you now smoke cigarettes?” and whether someone has smoked “at least 100 cigarettes” in their life.
“That’s kind of a weak variable,” Niaura said of the vaping question. “What does it mean? It doesn’t mean much.”
Further, the survey data don’t allow for analysis around timing, he said, meaning it’s impossible to tell whether someone developed liver disease before or after they began smoking and/or vaping. “What’s the resolution of the information in studies like this?” he asked. “It’s tricky.”
“It’s gratifying that the journal took the step to retract the paper,” Niaura continued. “There’s just a lot of things going on with this study that make it seem kind of weird.”
As Niaura sees it, many public health researchers have been quick to frame vaping as a threat to be avoided, and other scientists are now “playing catch up” to balance the debate.
“Right from the get-go, when e-cigarettes became a thing and the object of research interest, it appeared that everyone was out to discover their potential harms, and that’s continued,” he said. “Then some people started scratching the surface and saying, ‘Maybe these studies are not so good.’”
The ideological divides are sometimes stark. “It’s very frustrating, because if you start being critical of a lot of these studies, you get accused of working for the tobacco industry, for example,” Niaura said. “But in fact—and I’m part of the group that’s very critical—it’s really just standing up for science.”
“Once the bad fact gets out there, it’s like, who does the cleanup?”
A major worry is that once a flawed study is published, it’s difficult to ensure that the findings aren’t repeated elsewhere, whether in other papers or in meta-analyses that aggregate multiple articles, or in popular media.
“Once the bad fact gets out there,” Niaura said, “it’s like, who does the cleanup?”
One positive aspect of the retracted study, he added, is that it was based on public data, allowing others to review the authors’ analyses and conclusions. “If you can get reasonable people who disagree to then have an honest discussion about things that’s based on data, then to me that’s a positive outcome. The problem is we have too little of that.”
In a similar spirit of academic transparency, Niaura thinks Gastroenterology Research should publish the letter that led to the paper’s retraction. “People who wrote the letter—are they just grinding their axe, or do they have a legitimate claim?” he asked. “People need to know what’s going on.”
Correction, July 21: This article was edited to update Gregory Conley’s affiliation, which was previously out of date.
The Influence Foundation, which operates Filter, has received donations from the American Vaping Association, of which Conley was previously president. Filter’s Editorial Independence Policy applies.