Statistics indicate that hearing loss is on the rise. In this interview, board certified otolaryngologist Dr. Ford D. Albritton, IV describes the magnitude of the problem, as well as the research associated with key nutrients that can help reduce the risk of hearing loss. It's critical that all practitioners, not just hearing specialists, put this topic on their radar so they can help patients who already have hearing loss and those who are at risk.
Approximate listening time: 33 minutes
About the Expert
Ford D Albritton IV, MD, FACS, is the director of sinus surgery at the Sinus and Respiratory Disease Center at the Texas Institute for Surgery. He has served as chairman of the board of directors at the Texas Institute for Surgery and chairman of the Department of Otolaryngology-Head & Neck Surgery at the Texas Health Presbyterian Hospital of Dallas. Innovation and creative solutions to long standing problems in his field have been a focus of his practice since completing his training at the Emory University School of Medicine. He holds patents in the fields of nutritional compounds for targeting prevention of sensorineural hearing loss based on research initiated in the early 2000s. He also holds patents and expertise in the field of sinus disease and surgery with several publications to his credit. He remains active in clinical research and has been requested as a lecturer on the subject for surgeons domestically and internationally. Current interest exists in linking dietary methods of hearing preservation to cognitive function maintenance in patients with hearing disability, defining intervention strategy, and establishing modes of prevention.
Transcript
Karolyn Gazella: Hello, I'm Karolyn Gazella, the publisher of the Natural Medicine Journal. Today we have a fascinating topic. We'll be talking about how certain nutrients can help reduce the risk of developing hearing loss, and we have the perfect expert to help us with this topic. Dr. Ford Albritton, IV is a board certified otolaryngologist with the Sinus and Respiratory Disease Center at the Texas Institute.
Dr. Albritton, thank you so much for joining me.
Ford Albritton, IV: It's my pleasure, Karolyn. Thanks for having me.
Gazella: Yeah. So, how common is hearing loss, and have we actually seen an increase over the past decade or so?
Albritton: Hearing loss is incredibly common, and it's been pretty consistent if we look at the prevalence. The National Institutes of Health actually has its own group that looks at communication disorders, and they estimate the prevalence of about 15% of residents in the US having a diagnosis of hearing loss, and currently that puts us at about 38 to 40 million.
And you asked the question has there been an increase, and it's sort of a tricky answer. Yes, there's been an increase, but so has the population increased. In 1971, that number was 13.2 million and basically one third the current number.
So, why are we seeing such an increase? Well, it's a combination of population growth and the basic dynamics of our population age. If we look at aging as a criteria for hearing loss, we can compare people that are between the ages of 45 and 54. Only about 2% of those people are going to have a diagnosis of hearing loss, but if we go up to 75 years or older, almost one half to two thirds of the population will be having a hearing loss diagnosis depending on the studies you look at. And the World Health Organization has currently estimated hearing loss at about 466 million, but by 2050 they do predict that number should hit 900 million.
So, there's certainly an increase, but it's tricky to say that that's because of something changing in the environment or our susceptibility is increasing, and their point of fact is a few years ago, pediatrics journals documented that adolescents were having an increased rate of hearing loss from comparing data between '94 and 2006. They reviewed that data again in 2010 and found that that was just simply a statistical error and that they had erroneously just compared two points of data instead of contiguous and that actually the rate of hearing loss has not increased in that age group.
Gazella: Okay, that's interesting. So, what is considered a normal hearing range, and at what range does there begin to be a problem?
Albritton: The way we measure hearing is using something called an audiogram or audiometry, and it measures sound intensity. The official measurement unit is called the decibel, which is a logarithmic measurement of sound intensity, and we define normal hearing as a threshold where a subject can recognize a presented tone at a specific frequency less than 20 decibels. So, if you're presented a tone at a low frequency or a high frequency and you can perceive it, recognize it at a sound energy level quieter or equal to 20 decibels, that's normal.
Furthermore, we use some tricks of averaging and statistics to have some simple ways of measuring. Like we will average two tones or three tones or pitches on the hearing test and come up with a number of sound intensity, and we consider anything less than 20 normal, and anything above 25 we start to believe is abnormal and probably would benefit from some sort of intervention.
Gazella: Okay, great. So, let's talk a little bit about risk factor. Who's at risk of developing hearing loss?
Albritton: Probably a number one factor is family history. So, genetics play a larger role than we really can appreciate at this point in our mapping of the human genome, but family history is probably the most important question we ask patients into mapping their risk for hearing loss.
The second one would be noise exposures, people with a high occupational noise exposure. OSHA measures that as greater than eight hours exposed at 90 decibels, so noise exposure at that rate can cause hearing loss.
And then drugs; certain chemotherapy agents, some antibiotics are notorious for being toxic to the inner ear. Certain infections; one of the great benefits of immunizations and the reason we recommend immunizations is to prevent some of these preventable causes of hearing loss. Maternal infection of mumps, measles, rubella, for instance, can have devastating consequences on a fetal ear development and could have consequent hearing loss.
And then finally, sort of our chronic illnesses, diabetes, hypertension, heart disease can compromise blood flow and health to the inner ear causing problems. Inflammatory conditions such as rheumatoid arthritis, certain inner ear inflammatory conditions can also cause problems.
So, it's a pretty broad area of the things that can cause hearing loss, but the biggest risk, again, being family history.
Gazella: So, when we think of hearing loss, it's understood that it obviously affects communication and how we communicate with each other, but does hearing loss have any physical impact on a patient's life?
Albritton: That's an interesting question, and I think that 20 years ago we probably would not have directly thought so. It obviously does affect sense of wellbeing and ability to interact with others, but it can affect a lot of other things.
An interesting study from last February demonstrated a correlation of hearing impairment severity and the incidence of fractures to the radial forearm, to the hip, to the spine, and it showed that patients with severe hearing impairment actually had an increased risk of fracture that was greater than the normal hearing group, and basically you had 1.4 to 1.6 greater risk of having one of those types of fracture from a fall if your hearing was severely affected. There's lots of further digging that needs to be explored such as severe hearing loss also contribute to injuries to the balance system. That's sort of outside the scope of the research at this time.
But really the most newsworthy research in the past decade is focused on the correlation of hearing loss, severity of the hearing loss, with cognitive impairment and dementia. In 2013, a paper out of Johns Hopkins authored by Dr. Lin out of their department of otolaryngology and his colleagues demonstrated in just under 2000 patients that patients with a pure-tone average, that's that average we discussed earlier, of several frequencies of over 25 decibels, they had rates in decline in their cognitive function testing that was 30% to 40% greater than their normal hearing peers. And not only that, there was a linear relation between the hearing loss severity and the degree of decrease in their cognitive function test scores.
So, that data really set off alarm bells, and health organizations throughout the world, the British health system, the French health system, Danes, Italians began looking at their population, and probably the most robust examination has been the English, many thousands of patients, have agreed with this information. They put a cognitive impairment risk of 1.6 times greater than normal hearing population with hearing impairment.
Interestingly, some of these studies took the next step and tried to assess, well, if we do something for the hearing, such as a hearing aid or a Cochlear implant, something that will restore hearing, does that make a difference in the cognitive impairment testing? And it actually does.
An Italian study was one of the preliminary studies to look at this, and they demonstrated that either a hearing aid or a Cochlear implant could actually reverse some of this cognitive impairment seen on the testing with improved scores. The French study was pretty astounding in terms of its result. Greater than 80% of their lowest scoring cognitive impairment patients tested, they showed improvement after the Cochlear implant, which was quite surprising.
So, there's a question as to how hearing loss, how is this leading to dementia? And I don't think we fully understand that yet, though there are some hypotheses, and Dr. Lin laid out about four of these. First one being is there some common physiologic pathway that's contributing to both brain damage and inner ear damage? Something like blood pressure elevations where we see some chronic ischemic changes to the brain on MRIs or diabetes or something along those lines.
The second theory is something called the cognitive load theory. Basically, it surmises that the effort of constantly trying to comprehend what is being heard takes memory resources, whether it be a neurotransmitter or other nutritive resources, and the chronicity and cumulative nature of this leads to issues and errors in ongoing brain function, the ability to maintain memories in an ongoing manner.
A third theory is that hearing loss may affect brain structure. We do know that in brains of patients without stimulation, stroke patients, et cetera, that there's certain areas of the brain that shrink, and it isn't necessarily that we lose cells there, but there are some changes in the simple [inaudible 00:11:38] of those cells and that hearing loss patients do appear to show some of those similar findings on their MRIs.
And then finally, social isolation. We know that social isolation happens with hearing loss, and we also know that social isolation is a known risk for cognitive impairment. One theory that a lot of fellow ENTs and otolaryngologists specializing in ear have known about since the '90s is that if we fit a patient with hearing aids earlier, they do better long term, and a large study in the VA looking at World War II veterans in the '90s established that patients that obtained hearing aids earlier did better with those hearing aids long term. They were able to accurately repeat words presented to them at a higher rate than their peers who had not obtained a hearing aid and had similar hearing test results. They would have basically the same level of hearing loss, but their ability to interpret speech was impaired, and the ability for the hearing aid to function with those patients was just suboptimal and were not able to get the same level of functionality from their hearing aid.
And what the theory was is that the stimulation of certain areas of the cortical brain kept those areas healthy and functioning and that the old use it or lose it hypothesis, the patients who weren't using it did not maintain that brain and it therefore degenerated, never to really fully improve.
This takes it to another level and seems to suggest that it's not just those areas of brain corresponding to speech recognition; it's rather the brain as a whole that is suffering from the lack of input.
Gazella: Yeah. Early intervention is always best, so that makes a lot of sense. Now, you mentioned social isolation. Are there other areas that are affected with hearing loss that negatively impact the quality of the life of the patient?
Albritton: Well, I'm sure that there are, and I'm sure that we're going to discover more, but I think the most obvious is isolation and its consequential potential for depression. People that can't hear, they eventually will isolate themselves in social situations because it just becomes too embarrassing or futile for them to continue trying to participate in a conversation they can't hear. And I think we all can appreciate what that feels like. If we've ever been to a noisy restaurant and we can't hear the conversation across the table or slightly away from us, we tend to withdraw. Imagine that for patients with significant hearing loss being a daily ongoing issue, and that ends up contributing to further self-isolation, but depression, and several studies have demonstrated that there is an increased incidence of associated depression with hearing loss.
Gazella: Yeah, that makes a lot of sense. Now, you mentioned genetics. So, what is the difference between hereditary hearing loss and age-related hearing loss?
Albritton: I would suggest that almost all forms of hearing loss that we attribute to age probably have some genetic component. As we look at just genetic programming for your resilience, your resilience of your skin, your eyes, your hair, your ears, all of those things are sort of pre-programmed, and most people accept multi-hit hypothesis to hearing loss. In other words, that it's not one thing; it's a multitude of things over time that lead to the cumulative and irreparable damage and that there are certain susceptibilities imparted by our genetics.
So, we would guess that most age-related hearing loss does have some genetic, if not total genetic, predisposition, and the fact that it's not 100% of patients over the age of 75 with hearing loss, rather one half to two thirds, sort of backs that up.
But in terms of congenital or hereditary hearing loss, there are certain conditions and syndromes which we know are hearing loss related, and we can diagnose those fairly young. It's the patients over the age of 40, 50, 60 that we're less able to determine. And there are some studies, though, that have looked at what we term age-related hearing loss and looked at their genetics and have identified some mutations that are fairly specific for a family group but not universally represented in other genomic studies, and they show up in certain areas of the gene pool where we know that genes dedicated to hearing messaging are present.
So, there's probably a multitude of issues with mutations over our family histories that does lead to the age-related hearing loss, so I would look at them mostly in the same way.
Gazella: Yeah. It'll be interesting to see how that research kind of plays out from an epigenetic standpoint.
Now, there's early evidence showing that antioxidants, specifically beta-carotene, vitamins A, C, and E and magnesium can be protective. Tell us about that research.
Albritton: Sure. I want to add one more little point to the last question as it'll tie into this. We do know that insulin-like growth factor 1 is something that's important in our homeostasis and our ability to fight off reactive oxygen species or free radicals, and some studies have demonstrated that this decreases with age, and some other studies have taken it a step further and looked at does this have a role in some of the age-related hearing loss, and it does appear to have some role in that.
So, it's been a natural thing for antioxidants to have been targeted as a potential therapeutic arm against the aging of the ear. You mentioned vitamin A, C, E, magnesium, and I would caution drawing conclusions to these individual compounds at this time because the data is really all over the place.
There are numerous studies in mice that have demonstrated some general improvements using a group of different antioxidants versus control groups. Some of those antioxidants include things like cysteine or acetylcarnitine. Longitudinal studies, though, looking at humans with vitamins A, E, C, B12, folate have showed different results. For instance, in men, they didn't find any difference with any of those vitamins used except in men over the age of 60 they did note that folate may have given some protective benefit. In women, they found that vitamin A and folate also helped not necessarily an age dependent result, but this is interesting; vitamin C, which has been shown to be helpful in some animal models, was actually harmful and actually worsened things in some women studies.
We know that folate is an effective cofactor. We know that it helps balance out homocysteine levels, which can protect ischemic vascular damage, so that makes sense to us that it would work. The roles of vitamin C are just straight antioxidant properties, so that suggests that there's something more than just straight antioxidant benefits.
One interesting study in Finland that was done about 10 years ago, and they call it the disco study, and it wasn't a very large study; about 20 people were given either an antioxidant vitamin or a placebo. They had their hearing tested before a night exposed to loud music and then they had their hearing tested short term and long term afterwards, and they definitively showed that the group with the antioxidants had less impact from the noise exposure than the control group.
Gazella: That's interesting. I like they called it the disco study. That speaks to the era or the timing of that study, I think. So, when we're talking about studies, the research that I read I believe also included magnesium. What would be the connection with magnesium and why would magnesium help our ears? Am I correct? Was magnesium a part of that study?
Albritton: Magnesium's a part in several of these studies, and magnesium and the metals probably have a bigger role in enzymatic cofactor, enzymes that can control either the release of certain natural antioxidants or enzymes that have some role in keeping a biochemical process in its favorable state as opposed to going to its unfavorable state. Those metals are essential to these enzymes functioning theoretically, and yes, in some military studies, the use of magnesium has been shown to be effective.
Gazella: Now, you mentioned a lot of nutrients, A, C, E, just talked about magnesium. Is the combination of nutrients important and are there other nutrients that you wish researchers would be looking at?
Albritton: Now, you're getting to what my interest is. I think yes. I think very much there is combination therapy that makes a difference. I think we're still trying to figure out what that precisely is.
There are a host of readily available organic compounds that are something we may have picked up through ethnobotany or traditional Chinese medicine or just from the vitamin industry at large, but we have found that several of these compounds do appear to help in the protection of the inner ear, the heart, the kidney, et cetera.
One of those is N-acetylcysteine in rat models, which has proven to be effective at protecting the outer hair cells of the inner ear, and one of the methods we think it works is just by scavenging the free radicals, but it does turn on the body's natural production of glutathione synthesis. So, it doesn't just target the free radicals with its own ability to neutralize them. It actually turns on the body's ability to keep producing those free radical fighters.
But there's something else that goes on. It seems to regulate the nitric oxide in the inner ear, and one of the things that nitric oxide can do is, depending on its concentrations, it can trigger a cell to commit cell suicide. We call that apoptosis. In damage that may be sublethal, damage that shouldn't cause a cell to destroy itself, sometimes that misregulation allows the nitric oxide to get so high that it ends up allowing that cell to die. And as you may or may not know, these cells can't regenerate at this time, and so that regulation of the nitric oxide is one unexpected benefit of the N-acetylcysteine.
And that's something we see in several other compounds. Some compounds, for instance ... I'm just going to give you a brief list. Resveratrol. We know resveratrol as a miracle compound that has some anti-aging properties in animals, turns on some anti-aging genes, but we found in several studies that it has a highly effective role in reducing inner ear damage in animal studies. It has not been studied in humans to date. We believe that's a real key chemical.
CoQ10 has been also very effective in guinea pig models. We know that the mitochondria stabilization appears to be important, and CoQ10 is important in the function of our energy production in the mitochondria. Replacement does appear to have beneficial effects.
One independent observation as I see patients in my office all the time with a balance disorder that we can attribute to a medication being used for their high cholesterol, and a class of medications HMG-CoA reductase inhibitors, such as the statin drugs, are notorious for depleting the body's natural production of CoQ10. So, replacement of that in patients has helped with balance preservation, and anything that helps balance preservation we can assume is also working in other areas of the inner ear as well.
There are a number of elements and compounds that we discussed. We put together in 2006 a group of compounds we thought were going to be important that included the resveratrol, the N-acetylcysteine, N-acetyl-carnitine, alpha lipoic acid, green tea extracts, flavonoids from citrus, the CoQ10, B complex, and the trace minerals such as selenium, manganese, magnesium, and have found that to be effective in some pilot studies that we have performed on patients with their hearing loss showing some actual improvement in their hearing using the compound versus not using the compounds.
We've not had the opportunity yet to complete a double blinded study at this time, but there is certain promise with this. I think the holy grail is a compound that would be able to be taken on a daily basis that would offer protective benefits to the whole body, not just the inner ear.
Gazella: Right, and when you're talking about protection, you're even talking about protection in a patient that has some hearing loss; that it can also work in that patient population.
Albritton: Yes. In fact, our pilot study really only targeted patients with hearing loss. We compared patients that had many years of hearing loss, and we had multiple hearing tests on them and then started therapy with them and measured several hearing tests on the medication, were able to compare their hearing test pre and post, and were able to make those comparisons based on a preexisting condition. And so we did see some improvements in patients with existing hearing loss.
Gazella: What about reversal? Is that on the radar or is that a little bit too pie in the sky to actually reverse damage, to have a hearing be regained?
Albritton: There's research being done in terms of hair cell regeneration. That's several decades away at best. That, if it does prove possible, would reverse it.
Now, in terms of nutritional therapy, that's an unknown. We don't have the data yet to determine that. I think it is promising that we can see improvements in cognitive function with hearing aids and with Cochlear implants, but we can't know that by correcting some of the metabolic issues or protecting the interior from damage from its own physiologic stressors or noise exposures whether that's going to actually reverse the hearing loss that has occurred. I think that's probably pretty hopeful on our parts, but never rule anything out.
Gazella: Yeah. Yeah, that's for sure. Now, given how common hearing loss is, it's likely that the readers of our journal have patients in their practice who are at risk. So, in addition to the nutrients that you mentioned, what else should doctors be recommending to their patients to help protect hearing?
Albritton: I think first and foremost is recognize how common of a condition this is and screen for it. Ask patients, "Have you had any problems hearing? Has your spouse indicated that you may be having trouble hearing you?" It's interesting that spouses tend to be the ones that send patients for hearing tests more often than the patient seeks testing on their own. And it's a known fact that only one in five patients with hearing loss is going to seek help for it on their own typically. It can take 10 years or so before patients seek help for the symptoms.
So, it can lay dormant, it can be hiding and be attributed to mumbling or volume not being turned up loud enough before a patient truly begins to embrace there may be a problem they need to evaluate.
Refer patients for hearing tests if there is a presumed hearing loss or if there's a family history of hearing loss. Any patient that is on those medications, chemotherapy drugs, certain types of antibiotics, those patients should be monitored.
One other thing that I think is very important and I think most practitioners are very good about doing, but let's remind them that noise exposure can be prevented. If you can't prevent the noise exposure, then protect yourself from it and that people that have hobbies or occupational risks should be wearing some degree of hearing protection, and just like smoking cessation's important for us to counsel, the use and adoption of protective devices should be something we continually discuss at our meetings with these patients.
Gazella: Yeah, it's such a good point that you bring up that one in five seek help on their own and a lot just kind of let it go, let it go, and yet early detection, the earlier it's caught, the better off they'll be. So, I'm so glad that we're putting this on the radar of the doctors who are reading our journal. This has been very interesting, and I really appreciate you for joining me today.
Albritton: Well, thank you. It's been a pleasure.
Gazella: Have a great day.
Albritton: You as well.
