Vapor factory：The U.S. science and Health Commission questioned research on e-ci

On November 24, according to foreign reports, a new study found that if you smoke an electronic cigarette and then quit smoking, you are more likely to fracture than you are now. The authors say their results show that e-cigarettes pose a risk to bone health. What's the point? Let's take a closer look at this paper.

This paper was published by the American Commission on science and health and written by Cameron English, director of the Department of biological sciences. He is also the author, editor and co host of the podcast scientific facts and fallacies. Before joining ACSH, he was the executive editor of the genetic literacy program.

"There is more and more evidence against e-cigarettes. Now a new study links e-cigarettes with an increased risk of fracture. Recently, the media claimed that according to the report just published in the American Medical Journal Like many of the adverse effects allegedly associated with e-cigarettes, their hypothetical effects on bone health are only speculation at best. We can understand the reasons by comparing the media comments on the research and the actual content of the paper.

According to the press release, the researchers studied a sample of more than 5500 U.S. adults. Of the sample, 4519 (81.2%) had never used e-cigarettes, 1050 (18.8%) had used e-cigarettes, and 444 (8.0%) had brittle fractures. All these figures were reported as part of the national health and nutrition examination survey in 2017-2018.

Conclusion:

The results showed that the incidence of brittle fracture was higher in e-cigarette users than in non users. The researchers also found that the prevalence of brittle fracture was higher in people using both traditional and e-cigarettes than in traditional smokers alone.

First question: it has been widely proved that the harm of e-cigarettes is much lower than that of smoking, which may be 95%. According to this information, it is unclear why dual-use (almost always reducing the consumption of cigarettes) has a greater negative impact on bone health than traditional smoking.

In addition, "no significant correlation was observed between the current use of e-cigarettes and brittle fracture." the researchers wrote that "previous use of e-cigarettes was significantly correlated with brittle fracture." if e-cigarettes were a problem, it would certainly bring better results if e-cigarettes were no longer used. However, this was not found in the study.

Fuzzy definition

As we have seen in the previous e-cigarette study, the author's definitions of vaporization and smoking are so broad that they are basically useless. I doubt that's why their results are meaningless. If the study participants have smoked e-cigarettes at least once at any time in their life and at least once in the past 30 days, they will be punished Classified as current e-cigarette users. This includes people like me who use e-cigarettes many times a day and once a month. Anyone who has smoked at least 100 cigarettes in his life is classified as a former smoker. Among these people, "do you smoke now?" participants who answered "yes" are listed as current smokers.

The problem with these definitions is that individuals in the same category have very different exposures. For example, people who smoke one pack of cigarettes a month are much less exposed to harmful chemicals than those who smoke two packs a day. The same principle applies to e-cigarettes. E-cigarette users who take e-cigarettes once a month are exposed to propylene glycol and vegetable glycerin (VG) There are almost fewer opportunities than me. This is a common ingredient in e-cigarette liquid.

If e-cigarettes are a risk factor for osteoporosis - this is a huge "if" at present This study does not provide clinically useful data for the definition of current users. That is to say, consumers who eat a slice of French fries or eat 100 French fries at the same time are now at higher risk of type two diabetes. Now we know that this is a ridiculous correlation, but tobacco researchers often try to establish a relationship between electronic cigarettes and unhealthy health outcomes. Association with.

Strict restrictions

The researchers almost acknowledged this limitation and wrote "The granularity characteristics of e-cigarette use, such as the brand of e-cigarette use and the duration of e-cigarette absorption, cannot be systematically analyzed. They say so much is good, but why not do better research to let them answer these questions? The following are two other key details of the limited part of this study:

In addition, for some people, it is possible to start using e-cigarettes after the occurrence and diagnosis of fractures. In addition, this study did not analyze the relationship between current e-cigarette users who used to be traditional cigarette users and brittle fracture rate. This may bring broader clinical significance.

If participants start smoking e-cigarettes after a fracture, it is clear that e-cigarettes will not cause a fracture. The last sentence in the quoted paragraph is pleasantly ambiguous, but "broader clinical significance" It may mean that current e-cigarette users have a higher risk of fracture than non-smokers because they have smoked cigarettes for more than years. Of course, tobacco use is a well-known risk factor for osteoporosis. However, given the limited data contained in the study, we cannot address these possibilities.

The researchers claimed, "the potential impact of our findings on public health is convincing. With all due respect, any conclusion reached in this study is wrong. Long term exposure to e-cigarettes will certainly lead to bone damage, but we need to design better studies to reveal this relationship, if any