A striking new study led by researchers from the University of Nebraska has found unusually high levels of lead and uranium in urine samples from teenagers who frequently use e-cigarettes. But several scientists, while careful to say not vaping is still the safest option, have sounded the alarm over the study's design.
"I would classify it as yet another report intended to promote free-floating anxiety about vaping," said George Laking, from the Centre for Cancer Research as the University of Auckland. "To the extent it gets picked up, it is likely to cause active harm by scaring people back to smoking. One has to question the ethics of publication. It reminded me of the adage, widely used in public health ethics, about shouting ‘fire’ in a crowded theater just because someone lit a match."
The research in question has indeed been extensively 'picked up' this week, and for good reason: Unusually high levels of lead and uranium found in the urine samples of teenagers who frequently use e-cigarettes. The University of Nebraska researchers behind the study indicate that exposure to these kinds of metals can affect brain and organ development.
The findings come from data gathered in an ongoing project called PATH (Population Assessment of Tobacco and Health). This project commenced in 2011, tracking the long-term health effects of tobacco products.
The researchers focused on a wave of PATH data, collected between 2018 and 2019. Around 200 e-cigarette users were included, with an average age of 15. The cohort was divided into three categories: occasional users (vaping between one and five days per month), intermittent users (between six and 19 days), and frequent users (over 20 days). As part of the PATH study, all participants supplied urine samples allowing the researchers to track levels of metals including lead, uranium and cadmium.
The findings revealed lead levels in intermittent and frequent vapers were up to 30% higher than they were in occasional users. Uranium levels were also a concern, around twice as high in frequent users compared to occasional users.
While this paper is not the first to suggest e-cigarettes can expose users to toxic metals, several experts not affiliated with the latest research believe the findings are undermined by flaws in study design.
“There are so many sources of uncertainty about what’s going on here, and how the study’s findings can be interpreted, that I don’t think it can yet raise real health concerns," said Kevin McConway, Emeritus Professor of Applied Statistics, Open University.
Lion Shahab, from University College London’s Tobacco and Alcohol Research Group, noted that many of the exposure levels reported in the study are in-line with general population reference values. So the lead levels noted, for example, are not particularly higher than what is found in non-vaping adults.
“This study therefore cannot tell us anything about absolute increase in exposure to heavy metals from e-cigarette use in this population, only about relative exposure among less and more frequent e-cigarette users,” Shahab said.
“The authors have not thought critically about scientific inference from the data,” Laking added. “Their endpoint is a proxy for a whole body exposure burden. Urine is a route of excretion. What is going on with the participants? Are their urine metal levels at steady-state? Are they on the way up? Or the way down? Could it be possible that vaping is actually causing people to unload metals from other body compartments? Is this just noisy data in a smallish sample?
"The problem with vaping is it is addictive," he concluded. "Anxiety about addiction has spawned an industry that is trying to discover actual physical harms, so far without success. Meanwhile people are dying from smoking while they are scared away or even prohibited from vaping. Vaping is a far safer alternative way to deal with nicotine addiction."
The new study was published in the journal Tobacco Control.
Source: University of Nebraska Medical Center via Scimex
