Study Links Vaping to Stroke Incidence But Other Studies Report Otherwise

A new study says that just like smoking and dual use of vapes and cigarettes, vaping increases the risk for stroke. While a recent review covering 25 studies comprising 1,810 smoking participants, found that most tests indicated vapes do not bring any additional harm to a smoker’s health.

Titled, “The association between combustible/electronic cigarette use and stroke based on national health and nutrition examination survey,” the recent study was published in BMC Public Health. It analysed data for 4022 participants from the 2017–2018 National Health and Nutrition Examination Survey (NHANES).
After adjusting for a number of variables such as age and several health markers, the research team split the participants into three groups: those who used only vapes, those who only smoked cigarettes and dual users of both. The complied data indicated that all three groups were significantly associated with the prevalence of stroke, hence reporting no health benefit when switching from smoking to vaping.

However, the study does not mention whether participants who were sole vapers were recent smokers. Moreover, the participants where not asked when the stroke occurred, hence we do not know whether the actual strokes happened before or after any of the participants had possibly switched to vaping from smoking. Another flaw found in this study is that even participants who reported only using a vape once in their lifetime were classified as e-cigarette users. These factors make any associations between vaping and stroke too loose to be reliable.

Biased and flawed studies
In fact a review titled, “Clinical testing of the cardiovascular effects of e-cigarette substitution for smoking: a living systematic review,” examining multiple vape studies,  identified bias issues in many of them.

The review was conducted by In Silico Science, a project lead by CoEHAR, Center of Excellence for the acceleration of Harm Reduction, which aims to analyze the available scientific data for vaping products. The research team also evaluated studies for methodological biases and reporting issues, as well as the reliability of evidence.

“Twenty studies were rated at high risk of bias, and five as some concerns. A tabular synthesis by direction of effect was conducted due to heterogeneity in the data. Nearly two-thirds of the test analyses indicated that e-cigarette use had no significance difference compared with tobacco cigarettes on heart rate, blood pressure, and in other cardiovascular tests,” reported the researchers. They added that when smokers switched to vapes, no additional cardiovascular risks were observed and on the contrary some benefits were observed.

Benefits observed when switching to vapes
Meanwhile, another recent study published in Circulation, suggested that smokers who switch exclusively to vaping reduce their risk of heart disease by 34%. Using a longitudinal approach, the research team analysed data from 32,000 adult tobacco users who participated in the nationally representative Population Assessment of Tobacco and Health (PATH) over a six-year period from 2013 to 2019. The researchers assessed vaping and smoking patterns, and then compared them to incidences of self-reported heart disease, such as stroke, a heart attack and heart failure.

The compiled data indicated that compared to nonsmokers, smokers experienced a risk of heart disease that was 1.8 times higher, while the risk for exclusive vapers was not statistically different. To this effect, the study concluded that there is a significant link between smoking and heart disease, but not between vaping and heart disease.

Similarly, a randomized controlled trial looking into the medium and long term effects on heart health when smokers attempt quitting by switching to vapes, suggested that  nicotine consumption via vapes has the same advantages as traditional NRTs such as patches.

Titled, “Medium- and longer-term cardiovascular effects of e-cigarettes in adults making a stop-smoking attempt: a randomized controlled trial,” the study compared the medium- and longer-term cardiovascular effects in smokers attempting to quit smoking by switching to vaping products.

A total of 248 participants were randomized to receive behavioral support in combination with either (a) e-cigarettes with 18 mg/ml nicotine, (b) e-cigarettes without nicotine, and (c) NRT, and followed up at 3 and 6 months.

The research team found a flow-mediated dilation (%FMD) improvement over baseline in all three groups. None of the groups (i.e., nicotine-containing and nicotine-free e-cigarettes or NRT) reported superior cardiovascular benefits to the others.