Hearing Loss and Painkillers
A study conducted by Dr Sharon Curhan and her colleagues at Harvard University has recently been published in the American Journal of Medicine that associates hearing loss with taking painkillers.
Whilst it has long been accepted that high doses of painkillers such as aspirin can cause hearing loss and tinnitus, this is the first time long-term low-dose use of painkillers has been implicated.
The drugs studied were aspirin, paracetamol (acetaminophen) and ibuprofen which are three of the most commonly used painkiller with 60 percent of people taking one of these pharmaceuticals at least once a week.
The painkiller and hearing loss study
The hearing loss study was a prospective one that followed 51,000 male health professionals aged 40-75 over the years from 1986. Every other year the participants completed questionnaires about their diet, health and medication use.
At the start of the study none of the participants had any hearing loss. However, nearly 3,500 were currently found to have some degree of hearing loss.
After adjusting for other factors such as age, weight and health conditions known to contribute to hearing loss, the risks of developing later hearing loss were as follows:
12% increased risk of hearing loss when taking two or more aspirin a week
21% increased risk of hearing loss if taking two or more ibuprofen or paracetamol per week
28% increased risk of hearing loss if regularly taking aspirin long-term
33% greater risk for regular ibuprofen and paracetamol users
However, there are some provisos:
This study could only prove association, not causation.
It did not examine why the participants were taking painkillers and it may have been their underlying health condition rather than the pharmaceuticals that accounted for their hearing loss.
The hearing loss was assessed by self-reporting and so was subjective rather than using any objective measure.
The study did not examine other possibilities that might explain their hearing loss such as their occupational and recreational exposure to noise.
The group studied were mostly white, male health professionals and the results may not apply to other populations.
The incidence of hearing loss
Our hearing was never designed for our 24/7 world full of noise and stimulation and alarmingly, approximately one in ten people under the age of 20 exhibit some permanent hearing loss as a result of excessive exposure to noise. And approximately one-third of people in their forties have some degree of hearing loss. By the age of 48 years of age, you have a one-in five chance of developing some degree of hearing loss over the next five years.
How hearing loss occurs
Physical damage to the ears
Hearing loss can be a result of a pre-existing abnormality or physical damage to the hearing apparatus. Head injuries, for example, may result in temporary or permanent hearing loss or tinnitus.
Exposure to noise
Exposure to recreational or occupational noise can also cause permanent hearing loss. This can be the result of a one-off loud noise such as an explosion or can be cumulative.
Exposure to toxins
Some chemicals and pharmaceuticals are known to be particularly toxic to the ear (ototoxic). Typically, such hearing loss starts with the high frequency ranges and is permanent although in some cases may be reversible. Such chemicals induce lesions in the cochlea (inner ear) and others reduce blood flow to the inner ear affecting the translation of vibration into nerve signals.
The different ototoxins recognised to cause hearing loss are listed below:
Pharmaceutical drugs such as anti-malarial agents, antibiotics, non-steroidal anti-inflammatory drugs, chemotherapy drugs, diuretics and narcotic painkillers
Solvents such as toluene, styrene, xylene, white spirits, fuels, perchloroethylene and trichloroethylene
Toxic gases such as carbon monoxide and hydrogen cyanide
Toxic metals such as lead, mercury and organotins
Pesticides and herbicides such as paraquat and organophosphates
Hearing and painkillers: The take-home message
The moral is to look after your hearing - it cannot be recovered or replaced. Avoid of excessive exposure to noise, take antioxidants and be mindful that your painkiller habit may contribute to permanent hearing loss.