Thus, the effects of e-cig use that we estimate are I don't know when the paper will be published. [Epub ahead of print] In the data you looked at is it possible to tell if e-cigarette use was initiated before the myocardial infarction?It takes a long time from initial submission to publication and no author has control over that process. From the abstract it doesn't seem to be able to tell when e-cigarette use was initiated or when the MI happened. That is one of the limitations of all cross-sectional studies, which are a snapshot in time.
Moreover, studies are increasingly documenting that instead of prompting smokers to switch from conventional cigarettes to e-cigarettes or quitting altogether as some scientists and policymakers had hoped, e-cigarettes are reducing the likelihood that people will quit smoking, while also expanding the nicotine market by attracting more youth to start.
The new study from UCSF and George Washington University drew upon National Health Interview Surveys of 20 involving 69,725 people, and controlled for conventional cigarette use, demographic characteristics such as age, gender and body mass index, and health characteristics such as hypertension, diabetes, and high cholesterol.
Together they lead to five times the non-smoking heart attack risk in those who use both conventional cigarettes and e-cigarettes every day.
“The finding of increased heart attack risk for e-cigarette use, in addition to the risks of any smoking, is particularly troubling, because most people who use e-cigarettes continue to smoke cigarettes,” said senior author Stanton Glantz, Ph D, who presented the work.
We control for current and past cigarette smoking by including smoking status (never, former, some days, or daily) in the same logistic regression model as we include e-cigarette use (quantified the same way).
The effects of smoking and e-cigarette use are independent of each other and assessed at the same time.
That is why the cross-sectional studies are always done first.
Finding associations as we did between daily e-cig use and MI demonstrates the need for longitudinal studies.
Getting information on timing requires longitudinal studies in which people are followed forward in time, often for many years.
These studies take a long time to do (because you have to wait for time to pass) and are much more expensive to do than cross-sectional studies.