By Brian Taylor, AuD
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
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
