Experts question conclusions of study linking vaping and blood pressure

Public health experts have raised concerns about the interpretation of a new observational study examining the relationship between vaping, smoking and blood pressure.

The study, published in The American Journal of Physiology – Heart and Circulatory Physiology, analysed data from the US National Health and Nutrition Examination Survey (NHANES) and reported that people who smoked or vaped were more likely to have elevated blood pressure or hypertension than those who did not.

However, several researchers say the study’s design makes it difficult to draw firm conclusions about the effects of vaping.

Dr Nicola Lindson, associate professor at the Nuffield Department of Primary Care Health Sciences at the University of Oxford, said the research did not adequately account for participants’ smoking histories.

According to Lindson, the study identified smoking or vaping behaviour based only on whether participants had used these products in the previous five days.

“This means that past smoking history was not assessed,” she said.

She added that the number of participants who reported exclusive vaping was relatively small and it was unclear how many of them had previously smoked.

“As vaping is commonly used as a strategy for quitting smoking, we can reasonably assume that some of them had,” she said.

“This means that we cannot disentangle the effects of vaping from smoking.”

Prof Jamie Brown, director of the Tobacco and Alcohol Research Group at University College London, also questioned the conclusions.

He noted that smoking carries well-established cardiovascular risks and that combining smokers and vapers in the analysis could skew the findings.

“When looking among people who only vaped, the result was not statistically significant,” he said.

The study suggested that people who vaped were around five per cent more likely to have hypertension and about 15 per cent more likely to have elevated blood pressure, although Brown described these results as uncertain.

By contrast, the increases associated with smoking were much larger – 51 per cent for hypertension and 42 per cent for elevated blood pressure.

Prof Peter Hajek, director of the Health and Lifestyle Research Unit at Queen Mary University of London, said the study’s methodology was problematic because it combined results from smokers and vapers.

“The study uses an unusual approach in combining the results from smokers and vapers to claim that both are significantly associated with elevated blood pressure and hypertension,” he said.

Hajek argued that combining the groups diluted the results but still produced statistical significance.

A recent academic commentary has raised fresh questions about how evidence on vaping for smoking cessation is interpreted and communicated in research studies.