A new study investigating the effects of vapor from e-cigarettes is suggesting that long-term "vaping" could make people more susceptible to bacterial lung infections including pneumonia.
Last month the National Academies of Sciences, Engineering, and Medicine published a comprehensive report examining the health effects of e-cigarettes. While the study conclusively suggested that e-cigarettes certainly expose users to lower levels of toxic substances than conventional cigarettes, it also found that e-cigarettes are potentially acting as a gateway to conventional smoking in youth and young adults.
The long-term health effects of e-cigarettes are still fundamentally unknown and while they may be comparatively "safer" than regular cigarettes, recent research is building a case suggesting vaping may have its own unique set of harmful effects.
This new study focused on a molecule called platelet-activating factor receptor (PAFR), which is produced by the cells that line our airways. PAFR has been previously shown to help pneumococcal bacteria stick to airway cells increasing the risk of infections.
"Pneumococcal bacteria can exist in our airways without causing illness," explains lead researcher, Jonathan Grigg. "However, in some cases, they can invade the lining cells causing pneumonia or septicaemia. We know that exposure to traditional cigarette smoke helps these bacteria stick to airway lining cells, increasing the risk of infection. We wanted to see whether or not e-cigarettes might have the same effect."
The study included experiments in vitro with human cells, and in vivo with mice and human subjects. In both the in vitro cell tests and the human studies, the researchers found that vapor from e-cigarettes increased PAFR levels on airway cells three-fold. When pneumococcal bacteria was subsequently introduced to the airways of PAFR-elevated mice a higher volume of bacteria was found to stick to the respiratory tract of the animals.
"Together, these results suggest that vaping makes the airways more vulnerable to bacteria sticking to airway lining cells," says Grigg. "If this occurs when a vaper gets exposed to the pneumococcal bacterium, this could increase the risk of infection."
The study was small and not without its limitations, involving 17 humans participants. As well as not ethically being able to examine whether increased PAFR levels in humans actually increase pneumococcal infections, the results couldn't clearly determine the role that nicotine in the e-cigarette vapor played in potentially elevating PAFR levels. Certainly the results of the in vitro cell experiments suggested PAFR levels were elevated by e-cigarette vapor regardless of the presence of nicotine.
The study also isn't entirely clear how elevated the PAFR levels are by vaping in comparison to conventional smoking. Peter Openshaw from Imperial College London succinctly sums up this concern saying, "Although it is possible that vaping might increase susceptibility to pneumonia, the effect is likely to be lower than from smoking itself. We need further research to determine the effect of vaping on susceptibility to pneumonia in comparison to smokers."
A recent statement from Public Health England (PHE), a UK government health body, is encouraging widespread use of vaping as a health initiative to help people quit smoking. PHE even goes as far as recommending hospitals sell e-cigarettes, allow vaping in private rooms, and allow them to be accessed via subsidized prescriptions as a smoking cessation aid. But on the other end of the argument is the continued stance from the World Health Organization claiming there is no strong evidence suggesting e-cigarettes help people stop smoking.
Ultimately while e-cigarettes are most likely not as harmful as regular cigarettes, they are certainly not harmless. And the long-term effects on humans will not be clear for decades to come.
The study was published in the journal European Respiratory Journal.
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