And how can we explain the FDA's failure to appreciate that smoking is much more hazardous than vaping? It is not based on solid scientific reasoning. Instead, it appears to be based on either politics or ideology.

Here, they find a correlation between e-cigarette use and higher and more sustained levels of smoking. But because this is a cross-sectional study, they cannot determine which came first. In other words, what is the direction of the causal relationship? Does the e-cigarette use precede, and cause, the smoking? Or does the smoking precede, and cause, the e-cigarette use?

1. "Indoor concentrations of CO and CO2 showed no difference between control and vaping periods."

Suppose that there are 1000 e-cigarette users who enter the cancer center with a diagnosis of cancer. Of these, an amazing 900 were able to quit smoking. However, 100 were very resistant smokers and could not quit smoking, even with e-cigarettes. Note that it would be these 100 resistant smokers who would be enrolled in the study. The 900 ex-smokers who quit using e-cigarettes would not be eligible for the study, because they no longer smoke.

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