Does Vaping Cause Diabetes? ACSH Publishes Another Rebuttal

Last month, Cameron English, director of life sciences at the American Council on Science and Health (ACSH), published an article debunking unreliable vaping research findings from the past year, listing seven questionable studies and refuting them one by one.

Recently, Cameron English published another article criticizing a new vaping study that claimed vaping may increase the risk of prediabetes. The article sharply criticized both this unreliable vaping study and the media outlets that quoted it out of context.

The full text is as follows:

Some recent studies have suggested that vaping is associated with bone damage, erectile dysfunction, smoking relapse, depression, and increased stroke risk. However, these studies linking such outcomes to vaping are not supported by convincing data, so we have previously published rebuttals to them.
As more vaping-related research results emerge, yet another questionable study has appeared before us, and many media outlets are still quoting it out of context or uncritically, using it to amplify the claim that vaping is harmful.

On March 2, a new study published in the American Journal of Preventive Medicine linked vaping to an increased risk of prediabetes.

The researchers analyzed data from 600,046 people who reported their vaping and cigarette-smoking history to the Behavioral Risk Factor Surveillance System (BRFSS) between 2016 and 2018. BRFSS is a CDC-initiated telephone survey program designed to monitor health-related risk behaviors, chronic disease, and the use of preventive services across the United States.

The data showed that the prevalence of prediabetes was 9% among people who used vaping products and 13.4% among cigarette smokers; among exclusive vaping users (people who had never smoked cigarettes), the prevalence of prediabetes was 5.9%, while among dual users of cigarettes and vaping products it was 10.2%.
The study concluded: “In this nationally representative sample of U.S. adults, e-cigarette use was associated with increased odds of prediabetes.”

However, like other unreliable studies, this one is based on incomplete data, and its conclusions are severely limited. At present, there is little reason to believe that vaping increases the risk of prediabetes.

1. Unreliable exposure data

The first problem—and I know I sound like a broken record pointing this out—is that the researchers failed to collect meaningful exposure data:

“Respondents were first asked: Have you ever used e-cigarettes or other electronic vaping products in your entire life, even just one time? Those who answered no were classified as never e-cigarette users.”

Those who answered yes were classified as e-cigarette users and then asked: Do you now use e-cigarettes or other electronic vaping products every day, some days, or not at all? E-cigarette users who answered every day or some days were classified as current users, while those who answered not at all were classified as former users.

As we noted in response to a recent study linking vaping to bone damage, answers to these questions do not provide an adequate assessment of vaping use. Substitute almost any other behavior for vaping and the problem becomes obvious. Classifying someone as a former chocolate user because they said they ate a Snickers bar once in their life clearly does not reflect their dietary habits. Asking whether they eat chocolate every day or on some days does not help much either. In this case, you need much more specific information about how much a person vaped, as well as what type of device and e-liquid they used.

2. Serious limitations

Things get worse when we look at the study’s limitations:

“Limitations of this study include self-reported tobacco use and lack of medical confirmation of prediabetes and other dietary information. BRFSS is a cross-sectional survey; therefore, causal relationships between e-cigarette use and prediabetes cannot be inferred. Another potential limitation is recall bias. In addition, the authors did not have information on weight gain among former e-cigarette users, which may have resulted in misclassification bias.”

Combined with the inaccurate exposure data described above, these limitations are enough to undermine the credibility of the study. The study authors also acknowledged that the associations they found were based entirely on self-reported data. In addition, they found that only a small portion of participants both had prediabetes and used vaping products during the study period. There is no way to know whether vaping caused these individuals to become prediabetic.

3. What about the mechanism?

This critical detail is also buried in the paper: the mechanism underlying any causal relationship between vaping and prediabetes is still not fully understood. Stripped of academic language, what this really means is that we do not know how vaping would cause prediabetes. #p#Page Title#e#

The authors cited one study showing that smokers had higher blood glucose levels than non-smokers after an oral glucose tolerance test, suggesting that nicotine might be the culprit in this study. But this could simply reflect other variables, such as smokers having poorer blood sugar control for other reasons; studies have found that smokers tend to eat fewer fruits and vegetables and exercise less than non-smokers. Conversely, some studies have also shown that smoking is associated with weight loss, which tends to reduce diabetes risk.

There is still a great deal we need to learn about the metabolic effects of vaping. Unfortunately, this study did not improve our understanding.