E-Cigs and Vaping: A Hazard to Hearing?

By Brian Taylor, AuD

Rob Swire
Rob Swire

A recent media report suggests the musician Rob Swire of the Australian band Knife Party suffered a sudden hearing loss, which he attributed to vaping. Given the rising popularity of vaping, this incident is cause for concern, as many anecdotal reports suggest vaping is a safer alternative to smoking.

The chemical propylene glycol, which is used as a solvent in some vaping juices, is known to be toxic to the auditory system (ototoxic). The ototoxic properties of propylene glycol have been a known since at least 1980 when applied directly to the ear using ear drops.

To date, propylene glycol effects when used as an inhalant have not been documented.

According to Dr. Bharti Katbamna, a professor at Western Michigan University,

 

“Even though propylene glycol (PG) acquired the GRAS (Generally Recognized As Safe) status from FDA in the 1990s for use in foods and products like shampoos, etc., there is no data or evidence that is it in fact safe for inhalation. Moreover, its concentration in e-cigarettes is 50-80% greater than a traditional cigarettes (e.g., R J Reynolds lists a max of 2% PG), so that the aerosol has a dominant content of PG and glycerol.”

 

Expert Explains Possible Effect of Vaping on Hearing and Auditory System

 

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Bharti Katbamna, Ph.D.

Dr. Katbamma, who has investigated the effects of smoking on the auditory system went on to say, “there is no direct evidence that PG may be hazardous to the auditory system, there is plenty of indirect evidence that it may in fact produce damage to the inner ear.  In the 1980s, PG was used not only as an ingredient in otic drops, but also to provoke an inflammatory response in the middle ear mucosa, in an attempt to model acquired cholesteatoma in various animal models.  All of these studies instilled PG in the middle ear and/or on the round window membrane{{1}}[[1]]Ikeda and Morizono, 1989; Spandow et al al., 1988; Morizono et al., 1980[[1]] and noted that it is absorbed rapidly, leads to a decline in cochlear microphonics/potentials, increases auditory brainstem response latencies of the initial waves, shows a dose-response relationship and in most instances, depending on the dosing, the effects may reverse with time.”

“Even though the mechanisms of action were not explicitly stated, a couple of studies alluded to disruption of strial cells{{2}}[[2]]The stria is responsible for maintaining the cochlear fluid environment and essentially generating the cochlear potentials[[2]].  Transient loss of hearing reported in the report appears to fit this pattern.  Clearly, the effects of PG and perhaps its synergistic interactions with the other contents of e-cigs, need to be researched to gain a better understanding of the mechanisms of inner ear injury.”

 

Vaping and Hearing Loss: A Cause for Concern?

 

Based upon what we know about PG and its potential effects upon the auditory system, vaping could potentially pose a risk to hearing. Individuals who vape are encouraged to seek the care of a physician or audiologist if they experience any changes in their hearing.

 

Disclaimer: HHTM readers are cautioned that strong language is used in some of Swire’s tweets in the link above.

 

*feature image courtesy of  www.vapour.co.uk

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5 Comments

  1. Could formaldehyde contribute to hearing loss? What the vaping industry fails to mention is that high power vaping can produce more formaldehyde than smoking cigarettes. In January of this year a letter published in the NEJM indicated that unmodified commonly available vaping gear could emit significant amounts of formaldehyde when used at high power levels. At that time significant amounts of the toxic gas was given off from a small tank by driving the coil with about 12 watts of power. Despite knowing about this problem some vaping manufacturers have now increased power to 17 watts for similar sized tanks and coils. No vaping shop or gear manufacturer appears to be testing for formaldehyde emissions even though accurate formaldehyde meters are inexpensive and have been readily available for years. We simply do not know how much formaldehyde is given off by high power vaping rigs.

  2. Hi Brian,

    Propylene glycol may exhibit greater oto-toxic potential while vaping due to greater sytemic absorption, the more significant risk to ones hearing by the user of smokeless cigarettes comes from the highly oto-toxic concentrated nicotine. Nicotine is a known vasoconstrictor, it damages the microcirculation, and depletes tissues of oxygen and nutrients leading to malfunction of the hearing organs. 40 mg of nicotine is known to cause acute respiratory failure, and death in adults in five minutes, Nicotine is the active ingredient in a number of pesticides, and overdosing on e-cigarettes can not only harm the cochlear and eighth cranial nerve, it can also prove fatal to the user. The literature supports the preceding comments.

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