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Posted by jader201 12 hours ago

Taxi drivers rarely die of Alzheimer's(theconversation.com)
216 points | 162 comments
cortic 10 hours ago|
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.

stymaar 1 hour ago||
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.
jvanderbot 24 minutes ago||
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?

cyanmoonx 38 minutes ago|||
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.

xvedejas 6 hours ago|||
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.
cortic 6 hours ago|||
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.

bob_theslob646 1 hour ago||
What happens in the age of self driving cars?
inigyou 1 hour ago||
No taxi drivers
boelboel 6 hours ago|||
This is mentioned in the article as well.
harrall 7 hours ago|||
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.

pibaker 2 hours ago|||
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.

Tadpole9181 2 hours ago||
Would this not be closer to saying Arnold Schwarzenegger should have tried exercising more?
hotstickyballs 4 hours ago||||
Collecting a bunch of covariates is never a substitute for recognizing that you can't force people to be taxi drivers for life.
eru 2 hours ago||
However, you might be able to find a natural experiment were taxi drivers were randomly prevented from continuing with their driving career?
asdfasgasdgasdg 2 hours ago||||
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.
jollyllama 1 hour ago||
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.
kfarr 2 hours ago|||
Learning new languages (and actually using them) is a great way to do this for all ages!
specproc 7 hours ago|||
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.
vlovich123 7 hours ago|||
> 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.

danw1979 6 hours ago|||
Adjusting for age seems like an indication to me
vlovich123 5 hours ago|||
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.

_kulang 6 hours ago|||
Adjusting for sample/population age is the simplest interpretation of that
Revanche1367 1 hour ago||
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.
j45 7 hours ago|||
Seems like a fair point.
rf15 7 hours ago|||
> CBA to look at the article

then don't post

specproc 4 hours ago||
Mate, you ever read a scientific paper? You dig regression? Did you read TFA yourself? Was I wrong?
christophilus 4 hours ago|||
Yep. Free solo climbers also rarely die of Alzheimer’s.
brucehoult 3 hours ago||
BASE jumpers and wing suit fliers too.
glitchc 9 hours ago|||
They are likely studying individuals that retired without getting fatally stabbed or shot on the job.
stackskipton 9 hours ago|||
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.

minraws 9 hours ago||
Also road accidents.
boelboel 6 hours ago||
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.
minraws 5 hours ago|||
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.

boelboel 5 hours ago||
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.
minraws 5 hours ago|||
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.

bastawhiz 5 hours ago||||
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.
Petersipoi 2 hours ago||
> 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.

markdown 6 hours ago||||
That's like, almost all of them.
mito88 6 hours ago|||
survivorship bias
Barrin92 9 hours ago|||
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

jrflo 9 hours ago|||
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
cromka 8 hours ago|||
People jump the gun to show their perceived intellectual superiority. Typically same kind of people are last to admit of a mistake.
usef- 4 hours ago||||
And then their comment also reliably becomes the top-voted comment in the post
Melatonic 5 hours ago||||
You actually read the link ?
Nasrudith 6 hours ago|||
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.
jodrellblank 3 hours ago|||
> "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/

mcmoor 2 hours ago||
Also https://journals.plos.org/plosone/article?id=10.1371/journal... and https://slatestarcodex.com/2014/04/26/stop-confounding-yours...
cromka 8 hours ago|||
" (...) 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."
dinfinity 8 hours ago||
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."

fsckboy 4 hours ago|||
>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!"

nephihaha 4 hours ago|||
>Taxi Drivers: The mean age at death is approximately 67.8 years.

Where? What country/ies?

ch4s3 3 hours ago||
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.
TacticalCoder 10 hours ago|||
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).

xhevahir 5 hours ago|||
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.
AngryData 21 minutes ago||||
Lower income, little physical mobility in their job, constantly breathing traffic fumes, and tire and brake dust would be my first suspects.
id 9 hours ago||||
Because it doesn't pay very well. Being affluent increases life expectancy.
inglor_cz 7 hours ago||
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.

ChromaticPanic 2 hours ago||
They are if you consider the amount of hours they work
coldtea 8 hours ago||||
>For from the look of it it doesn't look like an exceptionally hard job

Define "hard job". Carrying heavy objects?

apothegm 5 hours ago||||
It’s a very sedentary job, pretty much by definition.
wilburx3 9 hours ago|||
Getting stabbed in the neck by filthy street urchins.
smt88 7 hours ago||
Probably not smart to post something like this on the same message board you’re using to get a job
bezmi 3 hours ago||
A joke?
Dusseldorf 2 hours ago||
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?
mplewis 52 minutes ago|||
did you read the study
coldtea 8 hours ago|||
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.
brandonmenc 5 hours ago|||
Hilarious, because accounting for this stuff is drilled into your head when you study the softer sciences (like psychology) even as an undergrad.
mr_mitm 7 hours ago|||
Next up: "I didn't do a statistical analysis but the sample size seems small"
heckelson 5 hours ago||
... in mice!
nuxi 9 hours ago|||
De Niro is 82, no Alzheimer's. /s
sillyfluke 7 hours ago||
He was method acting, so I'll allow it.
aaron695 3 hours ago||
[dead]
msuvakov 25 minutes ago||
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...
walthamstow 11 hours ago||
> 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.

neuralkoi 6 hours ago||
They have to memorize 25,000 streets. The test is no joke. [0]

[0] https://www.youtube.com/watch?v=ur61kzXjvN8

genxy 9 hours ago|||
People who would pass The Knowledge test might already develop dementia at a much lower rate.
monster_truck 6 hours ago|||
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
codygman 43 minutes ago||
So towards the end it was like it went away?!
inglor_cz 7 hours ago|||
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.

graemep 10 hours ago|||
The first study referenced is in the US, and across 443 occupations.
cromka 8 hours ago|||
> 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.

artisinal 11 hours ago|||
Indeed. Elsewhere in the world taxi drivers just follow the GPS.
SoftTalker 11 hours ago||
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.

jerlam 6 hours ago|||
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.
stymaar 54 minutes ago||
> 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.

OptionOfT 10 hours ago||||
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.
Marsymars 2 hours ago|||
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.

clickety_clack 10 hours ago||||
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”.
kccqzy 7 hours ago||
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.

toast0 7 hours ago||||
Suction cup compasses are ~ $10 on amazon if it bothers you. Won't be in the mirror though.
OptionOfT 4 hours ago||
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?
pryelluw 11 hours ago||||
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.
al_borland 9 hours ago|||
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.
SoftTalker 9 hours ago||
And Chicago is one of the easier cities to navigate, as it's almost entirely a grid.
walthamstow 8 hours ago||
Yeah I don't think grids are comparable to old world cities like London
BrandoElFollito 8 hours ago|||
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.

intellix 5 hours ago||
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.

anonymousiam 4 hours ago||
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.
pier25 11 minutes ago||
Does gaming also use similar spatial skills?
sixo 7 minutes ago|
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.
YmiYugy 10 hours ago||
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.
jere 2 hours ago|
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).
chuckadams 12 hours ago||
The ones that do stopped being taxi drivers.
cobertos 10 hours ago||
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.

david-gpu 9 hours ago|||
A dense street network with complex intersections also means living in walkable urban cores vs car-centric suburbs.
Palomides 10 hours ago||||
or there's a million confounding factors around people living in dense cities versus rural areas
smolder 9 hours ago|||
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.
cjbgkagh 11 hours ago|||
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.
mattlondon 10 hours ago|||
I guessed the probably died in a car accident or of something related to pollution exposure or being sedentary their entire adult lives.
don_esteban 11 hours ago|||
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?

brikym 3 hours ago|||
McDonnald's customers rarely die of anorexia
philwelch 5 hours ago||
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.
lazyasciiart 1 hour ago|||
They’re working off occupation as reported on death certificates, so they say they are assuming it’s still accurate.
chuckadams 5 hours ago|||
Probably. I was just being a smartass, really.
amelius 12 hours ago||
Something with more data:

https://pmc.ncbi.nlm.nih.gov/articles/PMC3920458/

Heliodex 5 hours ago|
> 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?

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