Hearing Loss and APOE4: The Dementia Risk Nobody Checks

[0:00]The number one preventable cause of dementia is not sugar. It is not blood pressure. It is not even exercising. It is whether you can hear this sentence clearly. I carry two copies of ApoE4. So when I read that, I went looking for the catch. There isn't one. And whatever your genes say, this one is yours to fix.

[0:25]In 2024, the Lancet Commission on dementia 14 modifiable risk factors and things you can actually change by how much dementia each one accounts for across an entire population Sitting at the top was hearing loss. Roughly seven percent of all dementia cases on the planet trace back to it I'll be very precise because you should check me on this.

[0:54]One other factor sits level with it and it’a high LDL cholesterol. That's why we have so many videos on how to optimize your lipid, but everything else on that list ranks below them both So there's not a supplement. It's not a brain game. It's not a scan We're talking about your ears.

[1:13]The biggest lever almost nobody is pulling sits right on the side of your head. So let me tell you why this is important for me in 30 seconds So let me tell you why this is important for me in 30 seconds Basically As you may know, I carry two copies of the ApoE4 Gene, which is the gene variant that raises a person's baseline Alzheimer's risk.

[1:32]Two copies is the highest risk version there is. I'm a doctor of pharmacy by training, which mostly means I've spent a career reading the fine print on things people swallow with a lot of hope and not much evidence. So when this landed, I did the only thing I know how to do.

[1:48]I went and read everything. Some of you watching are carriers who found out the way I did sideways and by accident. Some of you have watched this disease take somebody you love and you have decided never again. And some of you have no idea what your genes say, and you would simply like to keep your mind for as long as the mind can be kept.

[2:08]So you are all in the right room, whoever you are, plenty of you already are doing the work. The labs, the diet, the training. Same thing for me. I basically got my ApoB down 39% stacked with diet exercises, a few other interventions and I boosted my VO2max by 31% I talk about all of that in other videos, but here is the part that gets me the one factor the Lancet Commission ranked well number one, you have almost certainly never had checked.

[2:38]And that isn't carelessness. It's that somehow nobody ever framed it as a brain thing. They frame it as a getting old thing and getting old things go quietly onto the someday list because there's no urgency somehow. So for the next half hour, you'll see how big this lever is in real numbers across three quarters of a million people.

[3:03]And you see the four roads your ears might be taking down into your brain. I will walk you through the only randomized trial anybody has ever run on this, including the pathway. It looked like a flop. And you live with the four step plan. I would run myself starting with a test that costs you nothing.

[3:21]And near the end I'm going to show you the study that complicates everything I am about to say. So whether you trust me than be impressed by me. So let's start with the size of the thing. How big is this? When I read the word number one risk factors, my brain basically did what yours just did.

[3:40]It felt all right. Prove it. So the receipts Researchers pooled fourteen long-term studies that seven hundred and twenty-six thousand, nine hundred people together and everybody started out without dementia in those courts. The hearing got measured. Then they were followed for years, and somebody counted who got diagnosed. Here's the honest way to say what they found.

[4:04]Over the years these people were followed, dementia was diagnosed in the hearing-loss group at roughly one and a half times the rate. So we're talking about the hazard ratio of 1.59 A hazard ratio is just a speedometer for a diagnosis. 1.59 means it was showing up about one and a half times as fast as the general population And for Alzheimer's specifically, the diagnosis most of us are actually frightened of, it was diagnosed at more than twice the rate so we're talking about the hazard ratio of 2.24 so one caveat And I'm holding onto it for the whole video.

[4:40]And you should do this is what we call an association These are people watched over time not an experiment. Nobody can tell you hearing loss flipped the switch by itself. We can just say that it was associated with it. But if you look at the range around that first number, it runs from 1.37 to 1.86, and it never once touches 1.0 So in plain English, this is not a fluke that washes out when you look again.

[5:09]It showed up again and again and again across three quarters of a million people. And that's a lot of people. So we're not talking about the rounding error. That's basically you're hearing talking to your brain. Now let's have a quick chat about your genotype Does it get you out of it.

[5:26]So let's get the answer straight. If you carry ApoE4 and you're hoping this one skips you. I've got news. The researchers behind that analysis asked basically the same thing. Maybe the hearing link is really just ApoE4 hiding inside the data Bad genes causing both both the hearing loss.

[5:43]And that is along with all the other issues that we face as ApoE4 carriers. So the researchers went back and split the studies by whether they had already adjusted for the ApoE genotype. The link held either way. Same direction, no meaningful difference between the two So sit with that because it cuts both ways at once.

[6:03]The hearing risk doesn't run through your genes, it sits on top of them. And unfortunately we don't get the past. And that is precisely why it's worth your afternoon. A lever that works independent of our genotype is a lever you can pull no matter what you inherited. The gene is not the thing standing between you and this one.

[6:23]Your genes don't get you out of this, but they don't lock you out of fixing it either. Now, the skeptic in you is still probably sitting there muttering All right, all of that is association. And I'll be honest, like, the more I read about all these studies, the more you realize that a big majority of studies about alzheimer's about cognition, about dementia is association, association and association.

[6:44]All right. So the most clever attempt anybody has made to get past that is if you are born with your gene variants at random before a single one of your choices get involved. So researchers asked a sideway questions

[7:05]If they do, there is a much stronger hint, of course, than watching people age, because nothing about anybody's lifestyle chose those variants. So what we're talking about here is called I've talked about it several times in other videos, and it all pointed in the same direction. A genetic tendency toward hearing impairment came with higher odds of dementia, an odds ratio of 1.74, and of Alzheimer's specifically, 1.56 An odds ratio is that speedometer's cousin that I mentioned earlier.

[7:36]It asks how much the odds shift, not how fast, which is the same direction The same team stacked thirty-one cohorts, nearly a million people, and landed the same direction at a smaller size They also found something worth knowing if you've been quietly squinting at menus lately. When hearing and vision go together, the risk climbs stepwise, worse than either one alone So to not oversell this result, you have to know that other groups have run the same genetic approach and found no causal signal at all.

[8:06]The genetics are suggestive. They are not settled, but stack it up anyway. three quarters of a million people in the cohort. The genetic experiments leaning the same way, every arrow pointing at the course. It's as much as a proof as we can find, I believe, and it's also pointing the right way.

[8:24]So now let's think about the mechanism. How does your ears drag your brain down? How does muffled sound out here turn into memory loss in there. So there are four different roles. The first one will change how you sit at the dinner table. So road number one we're talking about effortful listening.

[8:43]Here's the weird part. When you're hearing fades the sound isn't the problem. The decoding of the sound is, you know, the feeling of straining to follow somebody across a loud restaurant table. You can do it. You just cost you something. You have to focus really, really hard to get the same result.

[9:04]Now imagine that the cost of that never switches off. So imagine that every conversation, every day for decades. Basically, your brain runs on a limited pool of resources. If you spend a big share of that pool reconstructing what the sentence probably was, and then there's less left to hold on to what the sentence actually meant.

[9:23]Researchers call it increased cognitive load during effortful listening If part of the damage is a brain overworked just to follow a sentence, then handing the sound back cleanly hence those resources straight back to memory. Basically, straining to hear is straining to think. Every conversation becomes a tax road number two, it basically takes the room.

[9:45]That road runs entirely inside your own head. The second one runs out in the world and it's quieter than you would expect Literally picture the relative who slowly stopped coming to dinner. Not because they stopped loving anybody because the table got hard. Too many voices, everyone talking about each other and the effort of guessing at half of it is basically exhausting in a way that's humiliating to admit out loud.

[10:10]So they smile, they nodded in the right places, and eventually they just stop showing up. We call that a personality change, but it's not the personality change that's hearing loss quietly putting somebody out of their own life. In a national study that use real hearing tests, instead of asking people how they thought they were doing.

[10:26]adults with hearing impairment had significantly higher rates of social isolation. And that isolation independently tracked with more dementia So there are two things here. Not only one, the hearing loss is a risk factor. The isolation that travels with it is another. Whether they compound, nobody has shown yet, and the authors say so themselves Here's why.

[10:48]This is the road I find strangely you know hopeful. Loneliness is not a lesion, it is reachable. Plug the sound back in and whatever it does or doesn't do for your neurons, you also get the dinners back The phone calls, the jokes you stop catching and stopped asking anybody to repeat hearing loss doesn't just take the sound, it basically takes the room.

[11:06]That was road number two. All right, let's talk about the cause, the catalyst or the consequence. Right. So far, I've handed you kind of a clean story. bad hearing hurts the brain. Fixing the hearing will protect your brain because I try to be as honest as possible here.

[11:22]Here's the slight twist. Everyone assumes that bad hearing damages the brain. The real answer is much messier than that. And honestly, I think better. A 2025 review in the Journal of Neurology laid out three possibilities and pointedly refused to pick one. Hearing loss cause declined by starving the brain of input.

[11:42]It could catalyze decline by piling cognitive overload and isolation on top of whatever else is happening. Or it could be a consequence an early symptom, where the disease is already damaging the brain's hearing centers before it ever touches your memory And there's one line in that review that belongs to the carriers watching, because if you carry ApoE4 this is important, there's evidence that Alzheimer's genetic risk drives hearing impairment running partly through ApoE4 Meaning hearing trouble may be an early feature of the disease itself, not only a separate problem feeding it and then if all three seats, a fourth possibility shared biology, the same inflammatory processes chewing on the ear and on the brain at the same time, and the genetic work hints that this route

[12:27]runs independent of ApoE4 that same review calls the shared pathology idea poorly substantiated and declines to chase it so I don't hold it too close. It is the only road on this list I can put a number on. So I watch my hs-CRP a blood biomarker of inflammation, and I keep in mine under 0.5mg/l Now, you could read all that uncertainty as a reason to wait for somebody to sort it out.

[12:50]I honestly read it as the exact opposite. If hearing trouble can be a cause and the catalyst and an early warning light, then taking it seriously wins in all three of those worlds. Either you remove a risk or you caught something early. There's no version of this where checking your hearing hurts you.

[13:06]Whether it's a cause, a catalyst, or a consequence, it could potentially be all three, which is why you should act on your hearing. Mechanisms are a story about how something could work. So I want to know whether it does. And for decades, nobody had run the experiment. Then somebody finally did.

[13:23]And at first glance it fell flat on its face. The first time anyone tested this with a real randomized trial, it looked like a failure. The trial is called ACHIEVE published in The Lancet in 2023. Nearly a thousand older adults with hearing loss randomly assigned either to hearing aids with real audiologist support or to health education control, then followed through three years of cognitive testing.

[13:48]This was totally randomized, controlled and the kind of elegance that you should actually care. So the headline result, three-year change in global cognition was not significantly different between the groups Sit with that for a second. The single best test on whether hearing aids protects your brain came back for the group as a whole.

[14:06]Well, null But a null headline is not a null paper You read the whole thing because the researchers build something into the design from the start. ACHIEVE recruited from two completely different places. Three quarters were healthy volunteers who answered an ad. The other quarter, 238 people came out of ARIC a long, heart study, and they were older, carrying more risk factors already declining faster, the team pre-planned to look at those two groups separately before anybody saw a single result In that higher-risk group, three-year cognitive decline was forty-eight percent slower with hearing aids And when a follow up analysis sorted every participant by the predicted risk of decline, the people in the top quarter declined about sixty-two percent more slowly

[14:55]Now, to be exact. It means that hearing aids doesn't protect everyone. The trial's own conclusion says the benefit turned up in populations at increased risk for cognitive decline, not in populations at decreased risk So in the healthy volunteers it did basically nothing you could measure. So why are we focusing so much on that subgroup result.

[15:18]Because higher risk is plausibly us. Us ApoE4 carriers because our genotype, our baseline and everything that we mentioned before, unfortunately, there is no trial that measured hearing aids specifically in ApoE4/4 carriers. That trial simply does not exist. And by the way, this is why I built Phoenix. I deeply believe that the best trial is not run in a clinical, extremely robust setting that can't be reproduced, that takes decades to come out, that takes an amount of funding that will deter the majority of organizations to test on things that can't be sold.

[16:00]What I believe should be tested is how us ApoE4 carriers in our everyday life, how do we reduce our risk and how do we beat the odds? And that's why Phoenix exist. To run this real life trial with real carriers in their real environment, with all the constraints that real life exist, and measure what works for people in this environment.

[16:25]What works for people similar to you? Similar to me because when you run experiments with the Phoenix community, you're not only managed to decrypt whether an intervention works for you specifically, but then that knowledge is pulled back into the community knowledge using Phoenix AI that is trained on all the clinical trials and all the research paper written on ApoE4 And on top of that, layers that source of information on what worked for each member inside the community.

[16:55]So the more members we have in Phoenix, the more data points we have. Of course, it's not as robust as having a placebo, a control and having this clinical setting. But for us carriers, what matters is if something works or not, we don't really care if it was placebo, we don't really care if it's not reproductive or if something works for you and you don't get Alzheimer's.

[17:16]That's the only thing that should matter to you. And that's the entire idea around which I built Phoenix Having you run your own experiment and leveraging the data you generate to help other people, the same way the data generated by other members help you define which is likely to work for you.

[17:32]If you're interested, the link to join Phoenix is in the description below. All right, let's go back to hearing aid effectiveness, because that is the whole game. Are we looking at any hearing aid? You buy the thing and you get the benefit. So the newest and largest data set we have gives a much sharper answer than expected.

[17:49]Buying a hearing aid does almost nothing. Wearing one that actually works is you know what matters. So the one published in May 2026. So not too long ago, and it's the biggest looks we've ever had. Seven cohorts pooled together. We're looking at Sixty-one thousand people across thirty-three countries, followed for years Among people who used hearing aids at all, probable dementia was diagnosed at a rate about nine percent lower than in hearing-impaired people who used none. So that’s a Hazard ratio 0.91 Among the people who said their aids genuinely improved their hearing, that gap widened to about fourteen percent lower. Hazard ratio of 0.86 And among the people who said their aids hadn't improved their hearing? nothing

[18:32]Hazard ratio of 0.98, with a range straddling 1.0. Statistically indistinguishable from wearing nothing at all. So the honest asterisk again here. This one it is observational The authors write it into their own limitations, that they cannot definitively prove a causal relationship So again hold it loosely, but it lines up with the randomized trial and it rewrites the action item completely.

[18:56]The action was never buy a hearing aid anyone. It's get one that is fitted properly. Then go back and confirm the thing actually improves your hearing. A device has tuned, and living in a nightstand drawer is the version that does nothing. And now we have the data saying so out loud.

[19:13]The wind is in the fitting, not the purchase. Now, as promised, here is the four step plan for you. The first step here costs you nothing. Number one, get a baseline hearing test. Many audiology clinics do them for free, actually, and a lot of you could run a decent screening on your phone this afternoon.

[19:30]Do it before you think you need it. The whole point of this is in midlife and having a baseline. It's so important to see how it evolves. Step number two if you feel like there is a loss, get properly fitted by a audiologist Fitting is a real clinical procedure and the fitting is where the effect leaves number three.

[19:50]And that is very important. Confirm that it works. Go back and really check. Can I understand speech in a noisy room better than I could before? Because if the answer is no, that is on the personality flaw isn't you failing at hearing aids It's a tuning problem and tuning problems get fixed and you'll be so surprised the amount of hearing aids that are poorly tuned.

[20:13]Number four, and probably the most important here, is to wear them most of your waking hours, not just for specific event. The fourth step is not a filler in ACHIEVE That clinical trial. The hearing aid group wore them about seven hours a day, and their self-reported communication and the gap dropped by half.

[20:30]While the control groups actually got worse. Researchers call that target engagement. It's how, you know, the aids were genuinely in ears and genuinely working, which is the only reason the rest of that trial meant anything. That is basically the same logic around on my own cholesterol, but there is nothing exotic about it.

[20:46]I found the biggest lever I had and pulled it on every day through a long, boring stretch of months. Hearing is just the biggest event nobody seems to screen. So screen it, fix it, confirm it works, keep it in your ears. That's the whole thing. All right, before we close this video, I want to talk about the honest caveat because I promise you a specific study that complicates all of this.

[21:06]So let's go there because I believe this is where I earn your trust, because I have to be straight with you. There is a 2026 study that complicates everything that we discussed. It's in Jama Otolaryngology 312 older adults with MRI scans followed for three years. Actually watching the cortex thing in real time.

[21:25]And here's what predicted the thinning It wasn't peripheral hearing loss, the kind not your grandma measures. It wasn't hearing aids either. What predicted it was Central auditory processing, basically how well your brain pulls one voice out of a room full of noise. In that cohort, hearing aids showed no significant effect on brain structure and non cognitive decline So what do we do with this.

[21:49]Basically I think it's supposed the third pathway the uncomfortable one. That is it's a consequence not only a cause which is why those researchers say something genuinely useful. How well you understand speech in noise, maybe an early behavioral marker of neural vulnerability showing up before cognitive test captures anything at all.

[22:12]So I want you to read that as an opportunity instead of a threat. At least that's what I do, because I believe for the past 5 or 6 years, I've had increasingly difficulty hearing people in loud environments, and I'm fairly on at 36. So if struggling in a loud restaurant is an early signal, then every noisy restaurant you've ever sat in has been a free screening test for you that you are running on yourself without knowing it.

[22:38]It's also precisely the thing I told you to demand at step three. Make sure that whatever solution you have improves that test that you have in noisy environment. Now you know how I like to think about the interventions to do right? I like to think about them as no regrets move.

[22:54]So what happens if I'm wrong all along and in this entire video? Because that's the real question, isn't it? It's not what's proven. It's what you do while the proof is still being assembled. So when I studied pharmacy, they basically train you to ask one question before you hand anything across the counter.

[23:11]The question isn't, does this work? The question is, what happens if I'm wrong? So you have to run it both directions say I go and fix my hearing, and it turns out the hearing was never driving any of this. What did that cost me? Well, it cost me a fitting fee, a little bit of dollars for the hearing aid.

[23:27]A few weeks of the world sounding too bright while my brain recalibrate The ACHIEVE researchers put the safety part in writing these interventions confer essentially no medical risk so this is as strong as a no regret move as you can have, because there's literally no side effect. There is no negative medical outcome out of it, only a slight financial one.

[23:49]And you have to know the field isn't standing still. There's an observational study running right now called ARCH, comparing hearing aids against cochlear implants for slowing cognitive decline, with results due in 2029 The science is going to get sharper, and I'll cover it when it does so you don't have to wait until 2029 to book a hearing test in 2026.

[24:11]You don't need to be sure to act. You need the cost of being wrong to be small, and it is extremely small. So just do that one thing. Book the hearing test this week, not just this year. Don't delay things. If I learned anything since I started working on ApoE4 is that you should not delay things that are basically no regret, because remember, the number one preventable cause of dementia isn't your sugar intake.

[24:35]It's not your blood pressure. It's not even the lack of exercising. It is whether you can hear this sentence, this video clearly. I would actually love to hear your insights, because I'm sure among the viewers of these videos, some of you have tried hearing aids and you might have insights to share, so please share them in the comment I would love to get additional ideas what you did wrong, what you did right, the things that you wish you know before you started.

[25:02]I'm all ears and I think that will benefit everyone in the community. until next time, cheers!