Taxi Drivers: The mean age at death is approximately 67.8 years.
General Population: in the same dataset, life expectancy averaged 74 years.
The average age at which patients are typically diagnosed with Alzheimer's disease is 79.
People in these jobs don't live long enough on average to get diagnosed, at the same rate. The same effect will happen in any job that lowers your life expectancy.
It pains me to see such a low-effort contrarian comment at the top: as stated in TFA taxi drivers are below other profession when controlling for age, and there are multiple professions with lower life expectancy that still have significantly higher Alzheimer rate than taxi drivers.
Every top-level thread is like a multiple choice armchair takedown.
Here's an interesting counterpoint. "Unthinkable" presented studies of navigation tasks in 2D/3D and testing/training. Hippocampus measurements correlated with skill and training. Interestingly, this skill and training and measurements all correlated with beneficial responses in a disaster (as in, not panicking). Weird right?
Isn't the mean age simply brought down by the number who die at a very young age due to car accidents, robberies, and other reasons?
Not that cab drivers only live to 67 - many would still live to 75, 85, 95, but that occasionally a driver dies at 25 or 35 bringing the mean figure way down.
And how would you control for the causal possibility that those who will eventually develop Alzheimer's early on might tend to have undetectable memory issues that prevent them from becoming taxi drivers in the first place? You can't control for profession, since that's behind the very claim itself.
Its even worse than that, i can imagine people with undiagnosed early Alzheimer's self selecting for car accidents and cardiac issues through additional stress of mental fatigue while their brain tried to compensate for loss of function.
So you have people self selecting out of the profession, self selecting for early death within the profession, and on top of that, a general life expectancy discrepancy that is near impossible to adjust for.
Alzheimer's is an entirely different beast than normal mental atrophy and there are plenty of stories of otherwise intelligent people ending up with it.
I'm not saying you shouldn't try using your brain more but this is just like saying Stephen Hawking should have tried exercising more.
Could just be that whatever factor causes certain cabbies to live much longer than their cohort is also protective from Alzheimer’s. I guess they might have accounted for that too — I’ll have to look at the study.
Or, that if you can survive the thing that kills the rest of their cohort, it has beneficial tradeoffs. As in, perhaps smoking protects from Alzheimer's, if it doesn't kill you first.
Controlling for age in a profession with a high fatality rate like this seems like controlling for high alertness, consciousness, quick reaction times, and well restedness/low stress, low recreational drug and alcohol use.
Of those, sleep issues are highly correlated with Alzheimer's and also with auto accidents. Controlling for age alone here would select for low incidence of sleep issues.
> After adjusting for age, sex, race, ethnicity and education, roughly 1 in 100 taxi and ambulance drivers died of Alzheimer’s, compared with 1 in 60 people overall.
So no indication they accounted for the expected lifespan of the profession.
It’s insufficient. For example, the people who develop Alzheimer’s may for whatever reason may be less likely to survive the profession where Alzheimer’s is the cause of death (eg getting into a fatal car accident where undiagnosed early onset is the problem). Bus drivers typically drive the same route over and over and probably have safer trips overall than taxi and ambulance drivers.
It’s a plausible hypothesis but it’s really really hard to tease things out and controlling for age is the obvious thing but that doesn’t get you the conclusive result you think it does.
Indeed. I feel that although many people try to learn new languages, the intellectual stimulation provided by doing so is understated. Especially learning languages very different from your native language (grammatically, morphologically, etc.). It’s almost like finding new ways to think.
As the paper points out that's accounted for in the analysis, because shockingly enough to most internet commentators researchers know that they need to control for confounding variables
It's not necessarily about intellectualism. Science in modern times is plagued by publish or perish. Researchers just need to get things published to keep working, and negative results don't get published. So I think people often publish stuff without proper controls/missing confounding variables/inversion of causality/etc not out of ignorance, but because they know the conclusion is dubious - but if they don't publish, they're going to be out of a job.
I don't think many realize how huge the replication crisis is. You have 75% of studies in a leading social psychology journal failing to replicate. [1] Another replication effort on preclinical medical studies found only 11% were able to be replicated, a replication effort on cancer studies found the average effect size to be 85% lower than published, and much more. If you assume most science headlines, at least outside of the traditional hard sciences, are false - you're substantially more likely to be right than wrong.
They got trained to said assumptions by bad sensationalist 'science journalism'. Remember how power lines caused brain damage in children? Not through the magnetic fields or anything like that, but the lowered property values.
It's not violence from the job but their job was generally bad for their health in other ways. Sitting all day without getting up and driving around with windows down getting all this UV.
Also, older ones were exposed to a ton of cigarette smoke.
I could imagine taxi drivers have fewer fatal/grave road accidents than the average person or at most slightly more. They tend to drive in cities, are more trained, can't drink or do drugs on the job. For London only 1 taxi driver has died in a traffic accident since 2020.
I'm gonna go out on a limb and say that not even a double digit percentage of taxi drivers' careers are ended due to violent attacks. Taxi driver doesn't even appear in the U.S. Bureau of Labor Statistics top 20 most dangerous jobs.
That's actually crazy if that's as low as you dare guess. I would have easily guessed it was like, a fraction of a percent. 1 in 10 would be fucking nuts.
" (...) After adjusting for _age_, sex, race, ethnicity and education, roughly 1 in 100 taxi and ambulance drivers died of Alzheimer’s, compared with 1 in 60 people overall."
"For each occupation, we first calculated the percentage of deaths due to Alzheimer’s disease and the mean age at death in years (ie, average life expectancy). We plotted the association between these two variables, with each observation reflecting a single occupation. The purpose of this analysis was to illustrate the need to account for the person’s age at death since the risk of Alzheimer’s disease rises with age and therefore Alzheimer’s mortality would naturally be lower in occupations with a lower life expectancy."
>People in these jobs don't live long enough on average to get diagnosed
not to mention the other devil in these studies: some professions are statistically going to have the lowest rate of every possible disease. you can't just cherrypick outliers and declare "causal!"
In the US, but you’d likely see a similar effect in other places. Taxi drivers are highly sedentary and occupationally exposed to a lot more road pollution than most jobs.
That's very interesting but why do taxi drivers have a job that lowers life expectancy? Is it because they're sitting too much? Or because they're inhaling CO from cars too much? Or staying inside (the car) too much? Or is it just stressful?
For from the look of it it doesn't look like an exceptionally hard job (btw a brother of mine did years of "VTC": "Vehicule de Tourisme avec Chauffeur", basically high-end taxis without the "taxi" logo).
I did it, briefly, twenty-some years ago. Lousy job—sitting all day, irregular pay, danger, nasty fares, drunk fares, belligerent fares, fares who seem to have nothing better to do with their days than to find ways to cheat a driver. But the thing that really sucks is the hours: shifts are twelve hours long, either ending or beginning at 3:00am, and because your rental for the cab is highest at the beginning of your work week, descending every successive day (free on day seven), the compensation is structured so that you're making good money only by working a ton of hours.
1. They are hardly in the bottom quintile, where the income effect is large enough that it could actually shave 7 years off their life. I'd expect nightly work, irregular sleep patterns, too much fast food and maybe a higher frequency of smoking to do their part.
2. The original study didn't just study taxi drivers, but also ambulance drivers. I doubt that their life expectancy is that much lower.
might turn out that the next company they apply to is run by street urchins who don't take too kindly to the stereotype? or possibly humorless scolds who don't want their employees telling jokes in their free time?
I had to read this a few times to make sure I read it right
> After adjusting for age, sex, race, ethnicity and education, roughly 1 in 100 taxi and ambulance drivers died of Alzheimer’s, compared with 1 in 60 people overall
> In one landmark 2000 study, neuroscientists compared the brains of licensed London taxi drivers with those of people who did not drive cabs.
Location is very important here. London cabbies have to pass The Knowledge which is an extremely difficult memory exam that only people with particular kind of brain can do.
They could also develop it at the exact same rate and mask it effectively. Had a very sharp family member who was completely lucid through all of dementia, it was like watching a tape rewind. Got to meet each decade's version of them over a couple of years. Towards the end they were completely normal
Plausible, but then you'd expect to find the same effect in other people who passed similarly demanding tests once. For example in people who studied something geometry-heavy.
Also, The Knowledge Test is, IIRC, passed only once and then you do not have to retake it for the rest of your career.
If a test passed in your 20s or 30s predicted accurately a much lower incidence of Alzheimer's in your 60s, that would be a remarkably strong early signal. Not impossible, but worth extra scrutiny. For the vast majority of old age conditions, we cannot predict them so long in advance.
> that only people with particular kind of brain can do.
That's yours speculation, isn't it?Because if so, it would corroborate the same conclusion, i.e. if you exercise your memory regularly, you are less likely to develop Alzheimer's.
When I was in my early 20s I had a job delivering pizza. I very quickly learned the delivery area, I knew pretty much every street and alleyway and shortcut to get from one place to another. Much smaller than London but I think the human brain is very good at remembering routes and where things are in an area, as this would have been an evolutionary advantage (go out hunting and be able to find your way back). No GPS, didn't even carry a map with me. We had a large map on the wall at the store, and if I had to deliver to a street I didn't recognize I'd find it on the map, see where it was relative to the streets I did know, and then I never had any problem finding places.
There weren't a lot of taxis outside of major cities. I think widespread GPS allows ridesharing apps like Uber and Lyft to exist in suburbs and other places where taxis weren't a thing before, because it dramatically lowers the bar.
> There weren't a lot of taxis outside of major cities
What? In my country at least (France), taxis have been a thing even in the countryside for as long as cars existed (or rather, as long as the telephone has). And I'd be very surprised if that wasn't also the case in most of Western Europe.
In fact it's a much easier job when it comes to routing and knowing your passengers' destinations than doing it in a metropolis.
My 2019 car had the cardinal directions in the mirror (N, NE, E, ES, S etc). My 2025 does not anymore. I hate it. I think it helps to get that baseline of orientation, and then you look at the street numbers, and it all starts to come together.
My 2011 car had an auto-dimming mirror that my 2025 car didn't, so I ordered a replacement auto-dimming mirror off ebay which includes the cardinal direction LED. (And garage-door-controlling buttons.)
As a bonus you can even set your general location on the mirror for extra accuracy, since the earth's magnetic line directions differ a bit based on location.
Pretty much my only issue with CarPlay is that I can’t seem to set the map so that north is up. It turns everything into “third right ahead” instead of “this is just 2 blocks east of that coffee shop I was at last week”.
CarPlay is merely the technology of having your phone take over a screen in the vehicle. It’s not a mapping map. Plenty of mapping apps support north up.
But in any case, I found that if you want to remember routes, it is far better to study the route before you begin driving, and then not rely on CarPlay altogether. This gives you much higher awareness of street names and directions.
Same. First thing they had me buy was a map book with all the local neighborhoods. The map on the wall helped get shortcuts from others. This is where I learned the difference between the different kinds of shortcuts. Some saved time, others distance, and some even potholes. It was a fun time.
I suspect GPS has made this much worse. I shining example was an Uber I got in Chicago, where GPS doesn't work well due to all the buildings. The guy drove around the same block 3 times, blindly following the GPS. It was infuriating.
There is (or at least - was) a similar test for Paris taxi drivers. They needed among others to explain turn by turn the drive between two places indicated by the examiner.
I wonder how it will look when we start doing statistics on gamers, if AI doesn't destroy our brains first. Then it would be interesting to plot the different death by genre like for example strategy, FPS, puzzle, etc. Someone else asked about Chess players which is probably also related right.
My grandad essentially died of alzheimers and he just loved to sit and watch football all day where you don't really need to think much.
Could it be that the cause/effect relationship here is incorrect? Perhaps only people with the cognitive skills for complex mental maps and spatial reasoning can be effective at driving a cab, so driving a cab may not "protect" you from Alzheimer's at all, but people who have the skills to keep a job as a cab driver have a brain that is less susceptible to Alzheimer's.
I find the title highly misleading. The actual claim is a 40% lower chance (1 in 100 as opposed to 1 in 60) for taxi and ambulance drivers when compared to the average.
That’s a big drop but the title implies that Alzheimer’s is rare in taxi drivers specifically and I don’t think the difference warrants that claim whatsoever.
True, though the article does also mention another study not based on taxi drivers, but just living in high spatial complexity ZIP codes puts you at a lower risk.
> Research on cognitive maps points toward the same conclusion as the study on taxi drivers. In 2023, researchers ran a machine learning model on more than 22,500 people in a national dataset and were able to predict which ZIP codes had higher rates of Alzheimer’s with 84% accuracy based on how complex the environment was. Those living in spatially complex surroundings – the kind that force active map building, such as dense street networks with numerous intersections, diverse points of interest and landmarks, and multiple path options – were less likely to develop Alzheimer’s.
I know an 80 year old who was a commercial truck driver for decades and still has a strong mental map for a pretty vast area. Anecdata, but I find it interesting.
I would assume that the task of being a taxi driver would act as a near constant test for Alzheimer’s, would be interesting to do GWAS studies on older taxi drivers and compare against taxi drivers who quit earlier in their careers.
I was going to make the same wisecrack, but in seriousness I assume they're counting elderly retired taxi drivers as taxi drivers even if they stopped working years before their deaths.
> Risk adjusted percentages and mortality odds ratios were adjusted for age at death, sex, race, ethnic group, and educational attainment using logistic regression.
Adjusting for educational attainment is an intriguing choice. If higher educational attainment were to decrease risk of Alzheimer's disease, wouldn't this adjustment optimise out the factor that they're looking for?
Otherwise very interesting results and conclusions. Also what's up with the outlying occupation on the left side of the 1st 2 charts on page 3: "Personal care and service workers, all other" with a mean age of death of 50.65?
I have a feeling gaming is quite harmful for spatial skills in the long run, because you learn many different maps (often transient ones in rng-ed games), rather than one fixed one. I would not be surprised if an epidemic of early mental decline begins to show in gamers in coming decades. I'm 36 now and feel like my spatial reasoning is declining in a strange severe way.
One of the first things to go with Alzheimer's is spacial mapping in the brain so this makes sense. Your exercising daily a part of the brain that is involved.
In addition there's the social component of driving - you may not always want to talk to a Taxi driver but many people do. And ambulance drivers are often socializing with their colleagues
Driving also has a mix of reaction time based skills and hand eye and hand foot coordination. Overall it's pretty complicated.
Writing this I'm realising the final "Turing" test for AI might actually be just replacing the average Taxi driver. Can it drive a car, choose a route dynamically based on day and traffic and weather, and have a conversation with a wide variety of people and topics all at the same time ?
The overall dataset was very large (8,972,221 deaths), but only 1,348 ambulance drivers were included, and just 10 had Alzheimer’s disease as the underlying cause of death.
Such a small number of outcomes matter because statistical precision depends on the number of relevant events. With only 10 Alzheimer’s deaths, even a small change in the count could substantially alter the estimated association.
Taxi drivers provided more robust data, with 171 Alzheimer’s deaths among 16,658 decedents, but death-certificate Alzheimer’s mortality may not reflect how often taxi drivers develop the disease. Differences in diagnosis or cause-of-death reporting across occupations could influence the observed association.
The large overall sample does not eliminate uncertainty in the much smaller occupational subgroups, particularly among ambulance drivers.
Nonetheless, this is an interesting study and merits further investigation.
Taxi drivers in old days needs to remember the whole map of their city, I think that is an efficient exercising/training that recommended for anti-Alzheimer, just like playing puzzles or quiz for oldman? But nowadays it is all about google map, not so sure about the effectiveness.
Wasn't there some an article/video from somewhere where a man had worked in a hot environment (I think it was on a navy ship in the engine room) and even though his family had a history of Alzheimer's, he never showed any signs of it. Does anyone know what I'm talking about? (Might not be Alzheimer, might be thinking of another disease)
Something interesting that the original study looked at, but isn't mentioned in the linked article: this effect was not observed for non-Alzheimer's dementia deaths. There seems to be something specific to spatial reasoning and Alzheimer's.
Alzheimers has a very long development stage compared to almost all other dementia (Lewis body also has a long timeline, but none of the other forms has anywhere close to the known length for Alzheimer’s disease). The original study article has no causal analysis, so a simple explanation is that super early Alzheimers symptoms (possibly even undetectable ones outside the context of intense taxi driving) drives people to abandon their taxi- or ambulance-driving jobs and seek other forms of employment.
I wonder if alcohol consumption plays a role here, since it is a known risk factor for Alzheimer’s. A taxi driver who works 60 hours a week will have very little time left over for drinking, whereas pilots have relatively short work hours where they actually need to be sober.
You don’t need to be a full blown acoholic to be affected, it’s simply a correlation of more alcohol consumption to faster decline of the brain. Having a job that requires you to be sober more hours of the week might bump you into a lower risk category.
Perhaps specific types of thinking cause somewhat sustained brain activity during waking hours that mitigates adverse physical changes leading to Alzheimer’s.
The opposite of this is how sleep and unconsciousness allows the brain to perform cerebrospinal fluid transfer based maintenance routines via the glymphatic system, and why sleep is important to neural health.
My grandfather was a taxi driver and delivery driver for many years. He made it to 93 and I don't recall him dealing with any cognitive decline. He used to tell me different routes to get to a stadium that was closed before I was even born.
I wonder if the same is also true of other high-spatial-complexity activities like rock climbing and professional dancing? (Exercise level would of course be a counfounding varable to be eliminated in these cases.)
> London cabbies must memorize more than 25,000 streets within a 6-mile radius of Charing Cross, a challenge known as “The Knowledge” that takes three to four years.
What the hell. I passed all the test for driving cabs in Stockholm, Sweden. I had to memorize 20 regions in the city. I wonder if this requirement applies to all taxi drivers, including Uber.
No, it’s a licensed black cab thing. London has had mini cabs as well for many decades who didn’t need to study anything and were not even licensed till about 20 years ago. However, their downside is they have to be prebooked and can not be hailed on the street. Apps count as booking and not hailing I guess.
It seems common for taxi drivers to form a government-sanctioned cartel in order to limit the amount of competition. In the US this traditionally took the form of local taxi medallion systems, where there was a hard quota on how many taxis could be in the city. London's barrier to entry, unlike ours, at least guarantees a level of competence, even if it's excessive.
At least in the US, Uber and Lyft basically went around the taxi cartels. I'd assume that it wasn't easy for that to happen in Sweden though.
Most modern open-world games have waypoint indicators and on-screen minimaps, if not teleportation, because memorizing and navigating and traversing through the video game map is not particularly fun.
Some years ago I participated in a study where I lied down in an MRI machine and had to navigate in a video game maze. (Custom Half-Life 2 level, IIRC.)
Every 60 seconds or so I'd be teleported to a fresh location in the maze and given an instruction like "find the green door". I have no idea how I did compared to the other participants, but I found the maze/task to be both difficult and not at all fun.
The thing about taxi drivers is that they have something at stake, while video games have no fail state effectively. You can be punished in-game, but overall it does not matter.
Also video games in general are pretty derivative, so playing the same genre probably won't help much after a certain point. But playing different ones can be very helpful, I imagine (same with other mediums).
I assume there is enough variation to be aware of -- seasons change, constructions, car crashes, so you need to alter the route a bit. Today you have the maps with navigation, but I assume you still need to be quite aware on where to park, where is the best entrance to some places, etc. So you basically need to keep some fresh info on top of your mind.
Guys... Alzheimer's is 60-80% heritable, and driven largely by APOE genotype. No, you cannot get out of it with One Quick Trick. We have to find therapeutics to make real progress here.
This kind of misdirection is not helpful to the research community, or encouraging politicians to fund effective projects. Everyone WANTS a quick lifestyle change and will latch onto these things, but this is a real biological disease that needs real molecular fixes. Sorry, it's just how it is.
Half of people with Alzheimer's carry at least one APOE ε4 allele. However, a full quarter of the population carries that mutation, and most carriers never go on to develop Alzheimer's. Lifestyle matters a lot here.
This kind of misdirection is not helpful for educating people on changes they can make now to reduce their risk, rather than waiting for a silver bullet. Alzheimer's research is well-funded in the US as the octogenarians running our congress are personally invested in it.
My understanding is that there are forms of dementia more tied to genetics than "Alzheimer's". One that has links to genetics is Frontal temporal Dementia.
To the extent that lifestyle helps, which is not zero, you need to exercise. "Become a cabbie" is NOT an intervention that is going to help whatsoever.
I don't think "become a taxi driver" is a "quick lifestyle change".
Studies like this are useful inasmuch as they help us understand a disease more fully. Not sure what you mean by "misdirection"; the study's methodology seems sound?
Taxi Drivers: The mean age at death is approximately 67.8 years.
General Population: in the same dataset, life expectancy averaged 74 years.
The average age at which patients are typically diagnosed with Alzheimer's disease is 79.
People in these jobs don't live long enough on average to get diagnosed, at the same rate. The same effect will happen in any job that lowers your life expectancy.
It pains me to see such a low-effort contrarian comment at the top: as stated in TFA taxi drivers are below other profession when controlling for age, and there are multiple professions with lower life expectancy that still have significantly higher Alzheimer rate than taxi drivers.
"Low-effort"?
You literally made no effort, both on research and thinking side.
You did just spit random shit about "multiple professions" because the comment made you butthurt.
Keep riding your Rickshaw, and putting "senior dev" in your Bio on all social networks.
Just the top one?
Every top-level thread is like a multiple choice armchair takedown.
Here's an interesting counterpoint. "Unthinkable" presented studies of navigation tasks in 2D/3D and testing/training. Hippocampus measurements correlated with skill and training. Interestingly, this skill and training and measurements all correlated with beneficial responses in a disaster (as in, not panicking). Weird right?
Isn't the mean age simply brought down by the number who die at a very young age due to car accidents, robberies, and other reasons?
Not that cab drivers only live to 67 - many would still live to 75, 85, 95, but that occasionally a driver dies at 25 or 35 bringing the mean figure way down.
And how would you control for the causal possibility that those who will eventually develop Alzheimer's early on might tend to have undetectable memory issues that prevent them from becoming taxi drivers in the first place? You can't control for profession, since that's behind the very claim itself.
Its even worse than that, i can imagine people with undiagnosed early Alzheimer's self selecting for car accidents and cardiac issues through additional stress of mental fatigue while their brain tried to compensate for loss of function.
So you have people self selecting out of the profession, self selecting for early death within the profession, and on top of that, a general life expectancy discrepancy that is near impossible to adjust for.
What happens in the age of self driving cars?
No taxi drivers
This is mentioned in the article as well.
The study accounts for that.
Delay your aging by using your brain a fuck ton, all the time, learning brand new things nowhere near anything you already know.
Alzheimer's is an entirely different beast than normal mental atrophy and there are plenty of stories of otherwise intelligent people ending up with it.
I'm not saying you shouldn't try using your brain more but this is just like saying Stephen Hawking should have tried exercising more.
Would this not be closer to saying Arnold Schwarzenegger should have tried exercising more?
Collecting a bunch of covariates is never a substitute for recognizing that you can't force people to be taxi drivers for life.
However, you might be able to find a natural experiment were taxi drivers were randomly prevented from continuing with their driving career?
Could just be that whatever factor causes certain cabbies to live much longer than their cohort is also protective from Alzheimer’s. I guess they might have accounted for that too — I’ll have to look at the study.
Or, that if you can survive the thing that kills the rest of their cohort, it has beneficial tradeoffs. As in, perhaps smoking protects from Alzheimer's, if it doesn't kill you first.
Controlling for age in a profession with a high fatality rate like this seems like controlling for high alertness, consciousness, quick reaction times, and well restedness/low stress, low recreational drug and alcohol use.
Of those, sleep issues are highly correlated with Alzheimer's and also with auto accidents. Controlling for age alone here would select for low incidence of sleep issues.
Learning new languages (and actually using them) is a great way to do this for all ages!
Studies typically use regression to account for stuff like that. CBA to look at the article, but I bet any money that's controlled for.
> After adjusting for age, sex, race, ethnicity and education, roughly 1 in 100 taxi and ambulance drivers died of Alzheimer’s, compared with 1 in 60 people overall.
So no indication they accounted for the expected lifespan of the profession.
Adjusting for age seems like an indication to me
It’s insufficient. For example, the people who develop Alzheimer’s may for whatever reason may be less likely to survive the profession where Alzheimer’s is the cause of death (eg getting into a fatal car accident where undiagnosed early onset is the problem). Bus drivers typically drive the same route over and over and probably have safer trips overall than taxi and ambulance drivers.
It’s a plausible hypothesis but it’s really really hard to tease things out and controlling for age is the obvious thing but that doesn’t get you the conclusive result you think it does.
Adjusting for sample/population age is the simplest interpretation of that
Indeed. I feel that although many people try to learn new languages, the intellectual stimulation provided by doing so is understated. Especially learning languages very different from your native language (grammatically, morphologically, etc.). It’s almost like finding new ways to think.
Seems like a fair point.
> CBA to look at the article
then don't post
Mate, you ever read a scientific paper? You dig regression? Did you read TFA yourself? Was I wrong?
Yep. Free solo climbers also rarely die of Alzheimer’s.
BASE jumpers and wing suit fliers too.
As the paper points out that's accounted for in the analysis, because shockingly enough to most internet commentators researchers know that they need to control for confounding variables
https://www.bmj.com/content/387/bmj-2024-082194
Always insane to me how people will just read the headline of an article and point out "flaws" based on what they assume the article says
People jump the gun to show their perceived intellectual superiority. Typically same kind of people are last to admit of a mistake.
It's not necessarily about intellectualism. Science in modern times is plagued by publish or perish. Researchers just need to get things published to keep working, and negative results don't get published. So I think people often publish stuff without proper controls/missing confounding variables/inversion of causality/etc not out of ignorance, but because they know the conclusion is dubious - but if they don't publish, they're going to be out of a job.
I don't think many realize how huge the replication crisis is. You have 75% of studies in a leading social psychology journal failing to replicate. [1] Another replication effort on preclinical medical studies found only 11% were able to be replicated, a replication effort on cancer studies found the average effect size to be 85% lower than published, and much more. If you assume most science headlines, at least outside of the traditional hard sciences, are false - you're substantially more likely to be right than wrong.
[1] - https://en.wikipedia.org/wiki/Replication_crisis#In_psycholo...
And then their comment also reliably becomes the top-voted comment in the post
You actually read the link ?
They got trained to said assumptions by bad sensationalist 'science journalism'. Remember how power lines caused brain damage in children? Not through the magnetic fields or anything like that, but the lowered property values.
> "researchers know that they need to control for confounding variables"
'Why ‟controlling for a variable” doesn't (usually) work' - https://dynomight.net/control/
Other things that don't work, including four other 'controlling for a variable' entries at items 39 through 43: https://dynomight.net/things/
Also https://journals.plos.org/plosone/article?id=10.1371/journal... and https://slatestarcodex.com/2014/04/26/stop-confounding-yours...
They are likely studying individuals that retired without getting fatally stabbed or shot on the job.
It's not violence from the job but their job was generally bad for their health in other ways. Sitting all day without getting up and driving around with windows down getting all this UV.
Also, older ones were exposed to a ton of cigarette smoke.
Also road accidents.
I could imagine taxi drivers have fewer fatal/grave road accidents than the average person or at most slightly more. They tend to drive in cities, are more trained, can't drink or do drugs on the job. For London only 1 taxi driver has died in a traffic accident since 2020.
If you drive more you are more likely to be in an accident, that's just how roads and accidents work.
Sure they might be better and per unit of time they drive they must have miniscule amount of accidents.
But if there's a 0.001% chance per hour driven, then over enough hours a few accidents are inevitable.
They don't just add more hours of driving they replace a small amount of risky hours for a lot of hours of low risk if they change location/job.
Also Drivers are generally less likely to die in accidents in urban areas, on high ways it's different.
Pedestrians are a lot more at risk. So that's unsurprising that annually 1/2 taxi driver might be fatally injured in one.
But I would assume the ratio of other drivers to taxi drivers would be high enough that this number should be zero as well.
I'm gonna go out on a limb and say that not even a double digit percentage of taxi drivers' careers are ended due to violent attacks. Taxi driver doesn't even appear in the U.S. Bureau of Labor Statistics top 20 most dangerous jobs.
> not even a double digit percentage
That's actually crazy if that's as low as you dare guess. I would have easily guessed it was like, a fraction of a percent. 1 in 10 would be fucking nuts.
That's like, almost all of them.
survivorship bias
" (...) After adjusting for _age_, sex, race, ethnicity and education, roughly 1 in 100 taxi and ambulance drivers died of Alzheimer’s, compared with 1 in 60 people overall."
Yep.
"For each occupation, we first calculated the percentage of deaths due to Alzheimer’s disease and the mean age at death in years (ie, average life expectancy). We plotted the association between these two variables, with each observation reflecting a single occupation. The purpose of this analysis was to illustrate the need to account for the person’s age at death since the risk of Alzheimer’s disease rises with age and therefore Alzheimer’s mortality would naturally be lower in occupations with a lower life expectancy."
>People in these jobs don't live long enough on average to get diagnosed
not to mention the other devil in these studies: some professions are statistically going to have the lowest rate of every possible disease. you can't just cherrypick outliers and declare "causal!"
>Taxi Drivers: The mean age at death is approximately 67.8 years.
Where? What country/ies?
In the US, but you’d likely see a similar effect in other places. Taxi drivers are highly sedentary and occupationally exposed to a lot more road pollution than most jobs.
That's very interesting but why do taxi drivers have a job that lowers life expectancy? Is it because they're sitting too much? Or because they're inhaling CO from cars too much? Or staying inside (the car) too much? Or is it just stressful?
For from the look of it it doesn't look like an exceptionally hard job (btw a brother of mine did years of "VTC": "Vehicule de Tourisme avec Chauffeur", basically high-end taxis without the "taxi" logo).
I did it, briefly, twenty-some years ago. Lousy job—sitting all day, irregular pay, danger, nasty fares, drunk fares, belligerent fares, fares who seem to have nothing better to do with their days than to find ways to cheat a driver. But the thing that really sucks is the hours: shifts are twelve hours long, either ending or beginning at 3:00am, and because your rental for the cab is highest at the beginning of your work week, descending every successive day (free on day seven), the compensation is structured so that you're making good money only by working a ton of hours.
Lower income, little physical mobility in their job, constantly breathing traffic fumes, and tire and brake dust would be my first suspects.
Because it doesn't pay very well. Being affluent increases life expectancy.
1. They are hardly in the bottom quintile, where the income effect is large enough that it could actually shave 7 years off their life. I'd expect nightly work, irregular sleep patterns, too much fast food and maybe a higher frequency of smoking to do their part.
2. The original study didn't just study taxi drivers, but also ambulance drivers. I doubt that their life expectancy is that much lower.
They are if you consider the amount of hours they work
>For from the look of it it doesn't look like an exceptionally hard job
Define "hard job". Carrying heavy objects?
It’s a very sedentary job, pretty much by definition.
Getting stabbed in the neck by filthy street urchins.
Probably not smart to post something like this on the same message board you’re using to get a job
A joke?
might turn out that the next company they apply to is run by street urchins who don't take too kindly to the stereotype? or possibly humorless scolds who don't want their employees telling jokes in their free time?
did you read the study
Ah, the typical cheap HN reaction to a paper, along with "correlation is not causation", and as usual, for things already factored in into it.
Hilarious, because accounting for this stuff is drilled into your head when you study the softer sciences (like psychology) even as an undergrad.
Next up: "I didn't do a statistical analysis but the sample size seems small"
... in mice!
De Niro is 82, no Alzheimer's. /s
He was method acting, so I'll allow it.
I had to read this a few times to make sure I read it right
> After adjusting for age, sex, race, ethnicity and education, roughly 1 in 100 taxi and ambulance drivers died of Alzheimer’s, compared with 1 in 60 people overall
I would’ve thought the effects were more profound
When the original paper came out a few months ago, I vibe coded a quick reconstruction of the main results. Page has the interactive charts: https://suvakov.github.io/vibes/AlzheimerMortalityByOccupati...
> In one landmark 2000 study, neuroscientists compared the brains of licensed London taxi drivers with those of people who did not drive cabs.
Location is very important here. London cabbies have to pass The Knowledge which is an extremely difficult memory exam that only people with particular kind of brain can do.
They have to memorize 25,000 streets. The test is no joke. [0]
[0] https://www.youtube.com/watch?v=ur61kzXjvN8
People who would pass The Knowledge test might already develop dementia at a much lower rate.
They could also develop it at the exact same rate and mask it effectively. Had a very sharp family member who was completely lucid through all of dementia, it was like watching a tape rewind. Got to meet each decade's version of them over a couple of years. Towards the end they were completely normal
So towards the end it was like it went away?!
Plausible, but then you'd expect to find the same effect in other people who passed similarly demanding tests once. For example in people who studied something geometry-heavy.
Also, The Knowledge Test is, IIRC, passed only once and then you do not have to retake it for the rest of your career.
If a test passed in your 20s or 30s predicted accurately a much lower incidence of Alzheimer's in your 60s, that would be a remarkably strong early signal. Not impossible, but worth extra scrutiny. For the vast majority of old age conditions, we cannot predict them so long in advance.
The first study referenced is in the US, and across 443 occupations.
> that only people with particular kind of brain can do.
That's yours speculation, isn't it?Because if so, it would corroborate the same conclusion, i.e. if you exercise your memory regularly, you are less likely to develop Alzheimer's.
Indeed. Elsewhere in the world taxi drivers just follow the GPS.
We had taxis long before GPS.
When I was in my early 20s I had a job delivering pizza. I very quickly learned the delivery area, I knew pretty much every street and alleyway and shortcut to get from one place to another. Much smaller than London but I think the human brain is very good at remembering routes and where things are in an area, as this would have been an evolutionary advantage (go out hunting and be able to find your way back). No GPS, didn't even carry a map with me. We had a large map on the wall at the store, and if I had to deliver to a street I didn't recognize I'd find it on the map, see where it was relative to the streets I did know, and then I never had any problem finding places.
There weren't a lot of taxis outside of major cities. I think widespread GPS allows ridesharing apps like Uber and Lyft to exist in suburbs and other places where taxis weren't a thing before, because it dramatically lowers the bar.
> There weren't a lot of taxis outside of major cities
What? In my country at least (France), taxis have been a thing even in the countryside for as long as cars existed (or rather, as long as the telephone has). And I'd be very surprised if that wasn't also the case in most of Western Europe.
In fact it's a much easier job when it comes to routing and knowing your passengers' destinations than doing it in a metropolis.
My 2019 car had the cardinal directions in the mirror (N, NE, E, ES, S etc). My 2025 does not anymore. I hate it. I think it helps to get that baseline of orientation, and then you look at the street numbers, and it all starts to come together.
My 2011 car had an auto-dimming mirror that my 2025 car didn't, so I ordered a replacement auto-dimming mirror off ebay which includes the cardinal direction LED. (And garage-door-controlling buttons.)
As a bonus you can even set your general location on the mirror for extra accuracy, since the earth's magnetic line directions differ a bit based on location.
Pretty much my only issue with CarPlay is that I can’t seem to set the map so that north is up. It turns everything into “third right ahead” instead of “this is just 2 blocks east of that coffee shop I was at last week”.
CarPlay is merely the technology of having your phone take over a screen in the vehicle. It’s not a mapping map. Plenty of mapping apps support north up.
But in any case, I found that if you want to remember routes, it is far better to study the route before you begin driving, and then not rely on CarPlay altogether. This gives you much higher awareness of street names and directions.
Suction cup compasses are ~ $10 on amazon if it bothers you. Won't be in the mirror though.
I think I should be able to add it to the iDrive. How much did BMW save by removing it from the mirror? $0.05 / mirror?
Same. First thing they had me buy was a map book with all the local neighborhoods. The map on the wall helped get shortcuts from others. This is where I learned the difference between the different kinds of shortcuts. Some saved time, others distance, and some even potholes. It was a fun time.
I suspect GPS has made this much worse. I shining example was an Uber I got in Chicago, where GPS doesn't work well due to all the buildings. The guy drove around the same block 3 times, blindly following the GPS. It was infuriating.
And Chicago is one of the easier cities to navigate, as it's almost entirely a grid.
Yeah I don't think grids are comparable to old world cities like London
There is (or at least - was) a similar test for Paris taxi drivers. They needed among others to explain turn by turn the drive between two places indicated by the examiner.
Today this knowledge is arguably less useful.
I wonder how it will look when we start doing statistics on gamers, if AI doesn't destroy our brains first. Then it would be interesting to plot the different death by genre like for example strategy, FPS, puzzle, etc. Someone else asked about Chess players which is probably also related right.
My grandad essentially died of alzheimers and he just loved to sit and watch football all day where you don't really need to think much.
Could it be that the cause/effect relationship here is incorrect? Perhaps only people with the cognitive skills for complex mental maps and spatial reasoning can be effective at driving a cab, so driving a cab may not "protect" you from Alzheimer's at all, but people who have the skills to keep a job as a cab driver have a brain that is less susceptible to Alzheimer's.
I find the title highly misleading. The actual claim is a 40% lower chance (1 in 100 as opposed to 1 in 60) for taxi and ambulance drivers when compared to the average. That’s a big drop but the title implies that Alzheimer’s is rare in taxi drivers specifically and I don’t think the difference warrants that claim whatsoever.
Yea "rarely" is pretty misleading. It makes it seem like it almost never happens when it's just a slightly lower chance (if that's even true).
The ones that do stopped being taxi drivers.
True, though the article does also mention another study not based on taxi drivers, but just living in high spatial complexity ZIP codes puts you at a lower risk.
> Research on cognitive maps points toward the same conclusion as the study on taxi drivers. In 2023, researchers ran a machine learning model on more than 22,500 people in a national dataset and were able to predict which ZIP codes had higher rates of Alzheimer’s with 84% accuracy based on how complex the environment was. Those living in spatially complex surroundings – the kind that force active map building, such as dense street networks with numerous intersections, diverse points of interest and landmarks, and multiple path options – were less likely to develop Alzheimer’s.
A dense street network with complex intersections also means living in walkable urban cores vs car-centric suburbs.
or there's a million confounding factors around people living in dense cities versus rural areas
I know an 80 year old who was a commercial truck driver for decades and still has a strong mental map for a pretty vast area. Anecdata, but I find it interesting.
I would assume that the task of being a taxi driver would act as a near constant test for Alzheimer’s, would be interesting to do GWAS studies on older taxi drivers and compare against taxi drivers who quit earlier in their careers.
I guessed the probably died in a car accident or of something related to pollution exposure or being sedentary their entire adult lives.
Yeah, that was the first thing that comes to mind.
And the second thing: What about modern taxi drivers that rely almost exclusively on GPS?
McDonnald's customers rarely die of anorexia
I was going to make the same wisecrack, but in seriousness I assume they're counting elderly retired taxi drivers as taxi drivers even if they stopped working years before their deaths.
They’re working off occupation as reported on death certificates, so they say they are assuming it’s still accurate.
Probably. I was just being a smartass, really.
Something with more data:
https://pmc.ncbi.nlm.nih.gov/articles/PMC3920458/
> Risk adjusted percentages and mortality odds ratios were adjusted for age at death, sex, race, ethnic group, and educational attainment using logistic regression.
Adjusting for educational attainment is an intriguing choice. If higher educational attainment were to decrease risk of Alzheimer's disease, wouldn't this adjustment optimise out the factor that they're looking for?
Otherwise very interesting results and conclusions. Also what's up with the outlying occupation on the left side of the 1st 2 charts on page 3: "Personal care and service workers, all other" with a mean age of death of 50.65?
Does gaming also use similar spatial skills?
I have a feeling gaming is quite harmful for spatial skills in the long run, because you learn many different maps (often transient ones in rng-ed games), rather than one fixed one. I would not be surprised if an epidemic of early mental decline begins to show in gamers in coming decades. I'm 36 now and feel like my spatial reasoning is declining in a strange severe way.
One of the first things to go with Alzheimer's is spacial mapping in the brain so this makes sense. Your exercising daily a part of the brain that is involved.
In addition there's the social component of driving - you may not always want to talk to a Taxi driver but many people do. And ambulance drivers are often socializing with their colleagues
Driving also has a mix of reaction time based skills and hand eye and hand foot coordination. Overall it's pretty complicated.
Writing this I'm realising the final "Turing" test for AI might actually be just replacing the average Taxi driver. Can it drive a car, choose a route dynamically based on day and traffic and weather, and have a conversation with a wide variety of people and topics all at the same time ?
This test would be passed by a Waymo with ChatGPT.
The overall dataset was very large (8,972,221 deaths), but only 1,348 ambulance drivers were included, and just 10 had Alzheimer’s disease as the underlying cause of death.
Such a small number of outcomes matter because statistical precision depends on the number of relevant events. With only 10 Alzheimer’s deaths, even a small change in the count could substantially alter the estimated association.
Taxi drivers provided more robust data, with 171 Alzheimer’s deaths among 16,658 decedents, but death-certificate Alzheimer’s mortality may not reflect how often taxi drivers develop the disease. Differences in diagnosis or cause-of-death reporting across occupations could influence the observed association.
The large overall sample does not eliminate uncertainty in the much smaller occupational subgroups, particularly among ambulance drivers.
Nonetheless, this is an interesting study and merits further investigation.
Taxi drivers in old days needs to remember the whole map of their city, I think that is an efficient exercising/training that recommended for anti-Alzheimer, just like playing puzzles or quiz for oldman? But nowadays it is all about google map, not so sure about the effectiveness.
Wasn't there some an article/video from somewhere where a man had worked in a hot environment (I think it was on a navy ship in the engine room) and even though his family had a history of Alzheimer's, he never showed any signs of it. Does anyone know what I'm talking about? (Might not be Alzheimer, might be thinking of another disease)
Something interesting that the original study looked at, but isn't mentioned in the linked article: this effect was not observed for non-Alzheimer's dementia deaths. There seems to be something specific to spatial reasoning and Alzheimer's.
Alzheimers has a very long development stage compared to almost all other dementia (Lewis body also has a long timeline, but none of the other forms has anywhere close to the known length for Alzheimer’s disease). The original study article has no causal analysis, so a simple explanation is that super early Alzheimers symptoms (possibly even undetectable ones outside the context of intense taxi driving) drives people to abandon their taxi- or ambulance-driving jobs and seek other forms of employment.
I wonder if alcohol consumption plays a role here, since it is a known risk factor for Alzheimer’s. A taxi driver who works 60 hours a week will have very little time left over for drinking, whereas pilots have relatively short work hours where they actually need to be sober.
> A taxi driver who works 60 hours a week will have very little time left over for drinking
That's plenty of time to be a full blown alcoholic.
You don’t need to be a full blown acoholic to be affected, it’s simply a correlation of more alcohol consumption to faster decline of the brain. Having a job that requires you to be sober more hours of the week might bump you into a lower risk category.
Not to mention that your full time alcoholic isn’t taking 12 hour shifts off to be sober.
Seems strange to me that a specific type of thinking could influence something where most causes being investigated are physical
Unless the arrow of causality is the other way: those that would tend to develop memory problems do not become or remain as Taxi drivers.
Right, so we're speedrunning the studies here. Best to just stopover on TFA and see what they found.
For example, airline pilots do not have a reduced level of alzheimers deaths, and that _certainly_ is not a place where you can coast with dementia.
And taxi drivers have _increasing_ anti-Alzheimer signals - with time, the areas that are known to diminish grow _more_.
Not strange when you realize thinking is also physical.
Wouldn’t thinking be like exercise for the mind? And we know what happens to people that don’t exercise
Perhaps specific types of thinking cause somewhat sustained brain activity during waking hours that mitigates adverse physical changes leading to Alzheimer’s.
The opposite of this is how sleep and unconsciousness allows the brain to perform cerebrospinal fluid transfer based maintenance routines via the glymphatic system, and why sleep is important to neural health.
https://www.science.org/content/article/scientists-uncover-h...
My grandfather was a taxi driver and delivery driver for many years. He made it to 93 and I don't recall him dealing with any cognitive decline. He used to tell me different routes to get to a stadium that was closed before I was even born.
n=1
++n
How many elderly Taxi drivers die of traffic accident? Perhaps the job is culling the Alzheimer's sufferers before other symptoms and signs arise?
I wonder if the same is also true of other high-spatial-complexity activities like rock climbing and professional dancing? (Exercise level would of course be a counfounding varable to be eliminated in these cases.)
Any studies on chess player and Alzheimer's?
I love HN for articles like these.... hard to find intellectually interesting yet seemingly corner-case statistics like this elsewhere.
First rule of attentioneering - If it bleeds, it ledes
Second rule - Got edge case? Got headline!
> London cabbies must memorize more than 25,000 streets within a 6-mile radius of Charing Cross, a challenge known as “The Knowledge” that takes three to four years.
What the hell. I passed all the test for driving cabs in Stockholm, Sweden. I had to memorize 20 regions in the city. I wonder if this requirement applies to all taxi drivers, including Uber.
No, it’s a licensed black cab thing. London has had mini cabs as well for many decades who didn’t need to study anything and were not even licensed till about 20 years ago. However, their downside is they have to be prebooked and can not be hailed on the street. Apps count as booking and not hailing I guess.
It seems common for taxi drivers to form a government-sanctioned cartel in order to limit the amount of competition. In the US this traditionally took the form of local taxi medallion systems, where there was a hard quota on how many taxis could be in the city. London's barrier to entry, unlike ours, at least guarantees a level of competence, even if it's excessive.
At least in the US, Uber and Lyft basically went around the taxi cartels. I'd assume that it wasn't easy for that to happen in Sweden though.
Can video games provide similar benefits?
Most modern open-world games have waypoint indicators and on-screen minimaps, if not teleportation, because memorizing and navigating and traversing through the video game map is not particularly fun.
Some years ago I participated in a study where I lied down in an MRI machine and had to navigate in a video game maze. (Custom Half-Life 2 level, IIRC.)
Every 60 seconds or so I'd be teleported to a fresh location in the maze and given an instruction like "find the green door". I have no idea how I did compared to the other participants, but I found the maze/task to be both difficult and not at all fun.
I’m sure Crazy Taxi provides the same benefits! :)
If you can survive the high blood pressure!
The thing about taxi drivers is that they have something at stake, while video games have no fail state effectively. You can be punished in-game, but overall it does not matter.
Also video games in general are pretty derivative, so playing the same genre probably won't help much after a certain point. But playing different ones can be very helpful, I imagine (same with other mediums).
Yeah but, Taxi drivers usually don't hop around from place to place. They work in a specific metro area.
I assume there is enough variation to be aware of -- seasons change, constructions, car crashes, so you need to alter the route a bit. Today you have the maps with navigation, but I assume you still need to be quite aware on where to park, where is the best entrance to some places, etc. So you basically need to keep some fresh info on top of your mind.
Maybe when played at a high level. But too many games are too casual without much mental effort.
I mean, they should be. Games are for fun, not for work.
Taxi driver also live shorter lives than average, which would fit with lower levels of alzheimers. But interesting link nonetheless.
Age and life expectancy was controlled for in the study.
before or after massive use of navigation apps?
Eating eggs actually lowers the risk of Alzheimers.
Guys... Alzheimer's is 60-80% heritable, and driven largely by APOE genotype. No, you cannot get out of it with One Quick Trick. We have to find therapeutics to make real progress here.
This kind of misdirection is not helpful to the research community, or encouraging politicians to fund effective projects. Everyone WANTS a quick lifestyle change and will latch onto these things, but this is a real biological disease that needs real molecular fixes. Sorry, it's just how it is.
Half of people with Alzheimer's carry at least one APOE ε4 allele. However, a full quarter of the population carries that mutation, and most carriers never go on to develop Alzheimer's. Lifestyle matters a lot here.
This kind of misdirection is not helpful for educating people on changes they can make now to reduce their risk, rather than waiting for a silver bullet. Alzheimer's research is well-funded in the US as the octogenarians running our congress are personally invested in it.
My understanding is that there are forms of dementia more tied to genetics than "Alzheimer's". One that has links to genetics is Frontal temporal Dementia.
To the extent that lifestyle helps, which is not zero, you need to exercise. "Become a cabbie" is NOT an intervention that is going to help whatsoever.
> "Become a cabbie" is NOT an intervention that is going to help whatsoever.
How about promoting spatial awareness and reasoning exercises (which is the actual suggestion of the article)?
I don't think "become a taxi driver" is a "quick lifestyle change".
Studies like this are useful inasmuch as they help us understand a disease more fully. Not sure what you mean by "misdirection"; the study's methodology seems sound?