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.
Fella has read the article, has an argument and some stats. What more do you want from a comment? He isn't running a study.
Besides, the point is a good one. There are a lot of professions. If we glance at the underlying study [0] Figure 1 suggests that we'd probably expect to see an outlier or two in that mess just through chance, we're expecting a few p<0.01. Taxi drivers doing unusually well doesn't seem especially impressive in that light, especially since it is one of the professions that seem to die off rather young and we might expect one of those professions to do rather well on Alzheimers.
But after the study controls for age the starkness of the effect more or less disappears (eyeballing Fig 1, the 2nd graph).
It turns out that there is a profession with a lowest risk of getting Alzheimer's (duh, one had to exist) and it looks like a slight outlier (it's the lowest, we'd expect that one to look like a slight outlier). As outliers go it isn't that impressive, it looks like it is part of a fairly boring distribution. We just plotted 400 data points on the graph, the 1/400 chance weird data point is going to look a little weird. We're actually just reading a lot into the fact that the 2nd data point in ambulance drivers which isn't all that convincing.
Not to knock the study, I'm sure it is a great study. Lots of science done. They do good graphs and all that. But the study appears to be telling me that Alzheimer's is random with respect to occupation and ideally don't spend so much time on the road if you want to live to see old age.
> But after the study controls for age the starkness of the effect more or less disappears (eyeballing Fig 1, the 2nd graph).
Adjusting for age, Alzheimers deaths were 1/100 for taxi drivers, and 1/60 for the general public. That's extremely significant. However you feel about the graphs means nothing compared to the actual numbers presented here.
> I'm sure it is a great study. Lots of science done. They do good graphs and all that.
Your choice to be dismissively anti-science helps to explain the bad point you're making.
What makes you think that is significant at all? Anytime you take a lot of small subsets of a large random sample you expect to find outliers that look a lot like this.
Outliers, sure. Exactly like this though? That depends. Since this is a population then assuming a gaussian (which could well be wrong for a variety of reasons I'm just guessing here) what's sigma? If 1/60 is within ~3 sigma then sure. Otherwise no.
It needs more statistical analysis than I have the background to do. However all signs look to another variation of the replication crisis, which is more an more my default assumption when I see an observational study.
It's getting hard to find any study posted without a kneejerk "correlation does not equal causation" take as if that's not something researchers have to control for in order to even conduct the study in the first place, let alone publish
The institutional media departments, journalists, and headline writers add back in the insinuated causation and effect size as a routine matter. That way we can't find fault with the researchers for their clickbait study.
The article (and apparently the researchers too) advances the idea there's a causal link here, even though one is not shown by the research. They go so far as to generally prescribe spatial reasoning training as a way to reduce Alzheimers risk.
You might be tired of hearing "correlation does not equal causation", but it needs to be said here.
Their argument doesn't show that at all though, they make an argument against an age bias when the article explicitly says age is being controlled for.
> Figure 1 suggests that we'd probably expect to see an outlier or two in that mess just through chance, we're expecting a few p<0.01.
That's a valid point, and a much better criticism than the one I'm calling out. That doesn't redeem the original comment though.
A distinction is that Alzheimer's is in an uncommon category of mystery diseases.
If a study found people who swim regularly are are less likely to get heart disease, that wouldn't be very surprising because know a lot about why people get heart disease. Therefore it would be valid to insist on more rigour for accepting (swimming => less heart disease) because the only use of that information is for health advice.
However even weak statistical correlations can be a valid lead for further research into Alzheimer's disease if they suggest where to look. You don't need to prove that signposts are correct in order to use them.
If we read OP's comment closely, it appears to be technically correct. I can imagine someone not upvoting it because it seems to be generic, but there isn't anything wrong or low effort about with it. And I don't see where the stats came from if he hasn't read the article.
maybe it would help this thread to have someone explain exactly how they control for age, if everyone in the range they want to study, is already dead.
What is the actual process to control for age? This comes up a lot, and the only response is "oh, well, we controlled for that", well exactly how?
Seriously, I'm curious.
//lot of downvotes, not a lot of anybody actually able to explain it.
From Article, the age question does seem sketchy.
"Although proportional mortality analyses do not provide information about the population at risk, with careful selection of controls and risk adjustment for factors that may affect competing risks (eg, age, sex, and social class), these values can still serve as a useful indicator of variations in disease frequency across different occupations.16 17"
As long as a researcher said "we controlled for confounding variables," there are plenty of people willing to take it at face value.
It's really difficult (maybe not possible) to do that in these large retrospective studies. Shingles vaccine preventing dementia, GLP-1 drugs preventing just about everything, etc, etc. There are plenty of good faith critiques of this kind of work from actual medical researchers making essentially the same point as the OP.
Worth mentioning that controlling for confounders is hard, a reasonable prior is the null effect, and any time a researcher makes a mistake it produces a publication claiming a novel effect. You observe a set of publications concentrated with false positives as a form of selection bias. I wonder how many of the causal studies are reproduced by independent teams using independent datasets.
Plausible scenario. Individuals predisposed to Alzheimer’s experience different mental sharpness from birth and this makes them enjoy taxi driving less (more intense than long-haul trucking), and so they pursue taxi driving as a career at lower rates. Under this scenario, driving has no effect, it just induces a selection bias.
True. But, these are still odd outliers in terms of low life expectancy, and that's something that the actual BMJ article cited (https://www.bmj.com/content/387/bmj-2024-082194) or TFA talks about at all. The LE is low enough for both professions to be awkward.
I'm also a little concerned that the BMJ plot of risk adjusted mortality still shows a clear positive correlation with age at death, which I strongly suspect would turn out to be statistically significant. The adjustment does not appear to be correct, therefore, and while that might still preserve these odd findings, it's definitely not ideal.
The much better occupation, from the graph, is the third outlier -- mining and geological engineers. Life expectancy: 80.3, risk-adjusted mortality: 1.1%. Or, alternatively, economists are close too (80.6; 1.19%).
Aircraft pilots, btw, really were the opposite end of the scale (78.1; 2.3%), surprising enough to be noteworthy beyond a control (the BMJ article does discuss this a little, but seriously -- that's very surprising for a highly-educated profession).
A better low effort contrarian comment - isn't it that early symptoms appear less often with people with a "reserve"?
Being mentally active (or physically active?) IIRC makes actual plaques both less likely, but also less detectable - a taxi driver can forget 90% of what they know and still not get diagnosed because they don't get lost on the way to the shops. Also they are often masters of small talk.
This would suggest they'd need to control for method by which the alzheimer's was discovered. A quick glance seems to indicate they did not do this. This is not information available I guess..
I would suspect this would eliminate a lot of the experiments participants, as only people who go for regular cognitive check-ups might be eligible?
I cannot imagine there would be many people left who'd be eligible. I can only think of 1 person that does it.. and he obviously does it for the pure satisfaction of acing those cognitive tests, and not because he is showing worrying amounts of decline in his mental faculties.
The first question you ask when you read a paper like this is whether you think the authors actually did control for what they say they controlled for. Usually, they didn't.
If the "study" is interesting at all, it's because of the implication that driving a taxi somehow wards off Alzheimers... but at the cost of killing you before you get it.
I do wonder if you can truly control for it in this case, or if doing so doesn't in and of itself introduce a survivar bias that masks a reversal of causality. That is: could the taxi drivers who are already predisposed to have a lower chance of developing Alzheimer for other reasons also be the ones who are more likely to live to be older than the average taxi driver?
But on some level I understand the immediate low level criticism. Of course, it’s stupid to criticize something without reading about it. However, I’ve seen waaaay more studies which was made with even lower effort.
For example, the other day I wanted to figure out what’s the current state about whether gender equality causes measurable benefits for companies… and the studies are terrible. All of them. Most of them was about Norway, and almost all of them had a reference point in 2008, one of the largest economic crisis, and somehow most of them was even worse than this. They openly distorted statistics. Depending on what they wanted to achieve to one way or another. Even the most cited ones. It’s disgusting. The best ones could prove only that inequality is not inherent of economics, but social. But the agenda was different for them too, so they tried to lie something bigger, all the time, while this would be more than enough to support it.
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?
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.
Fewer car accident deaths, leading to more elderly people, which inevitably means a higher population of people with Alzheimers.
(Unless people highly predisposed to dying in car accidents are also highly predisposed to mudering people who will have, but don’t yet have, Alzheimers. But that seems sufficiently unlikely for the purposes of this hypothetical.)
Jokes aside, the serious answer depends on whether the link is causative or merely collerative.
I'm still waiting on someone unbiased to study the data and tell me something. Those who have obvious biases tell me self driving cars are good, but their bias makes them suspect sources. So far I've not found someone without an obvious bias who had the data and is talking.
At one point the amount of human induced accidents will increase since no human can account for sudden erratic brakes of a self driver, even though it predicted a correct incoming accident with another V2V connected car.
Is every case of dementia diagnosed accurately? Is there a difference between professions how likely their dementia is to be diagnosed accurately?
Is there a correlation between dying early and being pre-disposed to have developed Alzheimer if having lived longer? If there is, then the "correction" for age is not correct, because the correction assumes the fraction of the group that died early were equally likely as the rest of the group to develop the disease if they had not died early.
I don't know anything about Alzheimer but it doesn't seem unthinkable that the factors that cause people to die early also could also play a role in causing Alzheimer.
You could imagine that pre-diagnosis confusion relating to Alzheimer's increases the risk of traffic accident and kills taxi drivers, too. Might not operate for truckers as much because they're more likely to survive accidents.
> 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.
No. There are a lot of other comments on why many do not believe it.
There is no reason to believe they have enough data to adjust for any of their controls. It looks to me like they plotted everything and then found the "outlier" which statistically we know will exist in a true random sample.
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.
The article doesn’t say taxi drivers are immune to Alzheimer’s. It specifically talks about having more cognitive reserve, which means having “more brain” to atrophy. Essentially Alzheimer’s makes their hyper-developed hippocampus become that of an average’s person because they started off higher up.
Being intelligent doesn’t mean you still learn new things as you age. Using your brain doesn’t do anything, it’s using your brain in novel ways.
That companion is also bunk. Two entirely different diseases.
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.
The claim was learning is important. Not the ability to communicate with it. There are more than 7000 known languages in the world, study a different one every week...
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.
> 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.
| 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.
They claim to control for these factors in the 5th paragraph of the article here. Which is a standard thing to do in these kind of studies.
So you're point is either not relevant or that they didn't control for age correctly?
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.
> 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.
This is very true. In my PhD research, I managed to perfectly predict the placebo effect using a random forest. Now, this was actually due to sampling variance, and the finding went away when I averaged over splits.
I often wonder if I'd still been in academia when this happened, if I would have been able to resist the siren call of a Nature/Science paper (and the consequent career benefits).
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.
About that old Slate Star Codex article, I find it amazing that no one in that 70+ comment section of presumably smart and Rational people, bothered to look up to see if there were interventional studies on bullying.
Dan Olweus did several of them in the 70s and 80s, and fought to his dying day against programs which didn't have casual intervention studies backing them.
The 1/60 to 1/100 difference could be explained by just one small confounder that is impossible to cover for. Therefore in my opinion making any conclusions based on this study wouldn't be fruitful at all.
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.
>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!"
" (...) 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."
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?
> 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.
Would they typically also relearn this at intervals. If you take 5000 rides a year, maybe 2000 streets that is 23000 you didn't get to remember though experience.
> I am glad Uber plowed through various stupid regulations
What like safety checks?
London had a huge minicab system, which is very much not knowledge based. Addison lee also had internet booking of cabs way before uber, but with the advantage that cars were roadworthy and the drivers were safety vetted.
It's very comforting when your cabbie knows exactly where you want to go with one prompt, versus being with some uber droid who can't look past their phone.
Uber famously pulled out of Austin for a year because Austin wanted to require background checks with fingerprinting on Uber drivers. I don't really like their style of "plowing through" regulation.
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
I don't understand. Do you mean they were lucid, but they believed they were living in a different year? Like thinking adults were still children in school and wondering when dead people were going to call? That kind of thing?
More like literally rewinding through the decades. The 80s, 70s, 60s versions of him. The printing company CEO shaking my hand calling me Mr Monstertruck, the kid who just signed up for the marines wanting me to try on his fatigues because they didn't fit him right anymore but were perfect for me.
Stuff like "I'm your grandson, dadsnames kid" didn't parse at all, they said not to bring up shit like that so we didn't.
We had to move him into a house because he kept using his POW training to break out of the dementia ward. Pickpocketing keycards and shit, he was a badass till the end.
Kind of, you could tell it took a lot of effort. Usually after a full night of sleep and a good breakfast, or after a nap. A few of us had lengthy car rides where he said everything he wanted to
He told me he was so jealous of all this new computer stuff I get to play with. I think about that a lot this year
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 Test is repeated every day you get in the cab.
If you get into a black cab in London and ask to be taken to any location, anywhere within 6 miles of Charing Cross, that driver will know immediately the right route to take without satnav. To get to that point they need to know 25,000 streets and many, many landmarks - statues, museums, galleries, restaurants, hotels, and so on.
I used to regularly drink with a cabbie in London, and he said that every time somebody got in the back his heart rate would rise, as he'd realise he's "on" and about to have to work out where to head from scratch. Within 30 seconds he'd have every step of the way worked out, down to which lanes at which intersections, no matter where in London he was or where he was going.
That's the thing that's likely going to reduce Alzheimer's.
One of the things that seems effective in reducing Alzheimers is a "flushing action" inside of the brain (Glymphatic system). I wonder if this spatial reasoning maps into a spatial activation in the brain. It would be interesting to put London cabbies in an fMRI machine and have them plan routes.
It would also be interesting to look at sleep traces of cabbies.
> 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.
A number of the women in my wife's family have been diagnosed with Alzheimers. All of the women I know in her family also hate driving, because they find it very stressful.
It's plausible that people prone to Alzheimers are less likely to be comfortable driving.
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.
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.
I guess countryside France is still only 2 hours from Paris or Marseille, while countryside USA is maybe 8 hours or more from a metropolitan area. Not to mention that the population in this usa countryside is already way lower then any population density in the whole of France.
Operating a taxi corp there would simply be not viable on a financial term.
> I guess countryside France is still only 2 hours from Paris or Marseille
Not at all, it's more like 6 hours if you're in a somewhat remote place, but most taxi trips are way smaller than that even in rural area anyway.
> Not to mention that the population in this usa countryside is already way lower then any population density in the whole of France.
I don't think it matters, as there are plenty of rural places in the US that still have a higher density than where I live.
> Operating a taxi corp there would simply be not viable on a financial term.
Probably not a taxi “corp”, but here taxis have always been independent businesses with one or two cabs an providing taxi service on an area of a few hundred of square kilometers (a radius of 50km or so around the "office" of the taxi driver). And a large fraction of the trips are not on demand, but upon reservation several days in advance (you know you'll need to go to a medical appointment to the city next month, or you need a ride to the train station later this week).
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.
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.
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.
They have been reality for many years. A compass built into the car didn't exist in the 1990s (it probably did in luxury cars - I never drove them), then moved into mainstream cars, and now the fad is dieing.
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.
> These findings stopped me in my tracks because those two jobs rely on the same thing as my own work: maps.
Those jobs rely on navigation, not maps. Reading maps and navigating the real world are very, very different things.
The later point about zip codes with higher complexity is the same - these residents have to _navigate_ in more complex situations. How the author seems to be conflating that their personal job of staring at maps therefore protects them from Alheimers is very wishful thinking IMO.
Based on this data, I wouldn't be surprised if Google Maps has lead to a rise of Alzheimers.
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.
That’s an interesting point and we have not really had a reliable dataset to qualify individuals as “professional gamer/streamer” vs a hobbyist.
Their content publication history should be a good metric for establishing our future subjects and departed ones as engaging in above average gameplay for each specific genre.
I’ve always found it fascinating that I could recall essentially turn by turn navigation of WoW classic routes in which I spent countless hours. I’ve always thought about trying the memory palace technique and using those routes which would probably work well.
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.
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.
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.
Accidentally stumbled on an ESRI's GIS for Scienece volume... there was a cited evidence of MRI scans of high-scholers brains, monitored while kids develop spatial reasoning skills. Well the images definitely showed prefrontal cortex better developed, only after an year. So this is more than anecdotal evidence.
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 ?
> 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?
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 the usage of mobile navigation will increase Alzheimers for our generations.
When driving I either now the way or use maps, there is rarely any guesswork or active thinking involved, maybe running is helping but even there I sometimes run routes navigated by watch.
Purely anecdotal, but I experimented with getting rid of my phone entirely for 6 months (using VoIP on my laptop for calls and text), which meant I had to plan my route ahead of time using online maps (OsmAnd). I found that my short-term memory improved noticeably and I could easily recall 10 digit numbers I just saw briefly.
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.
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 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
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.
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.
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.)
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)
might want to look into statistics on ppl who play a lot of first-person shooting games. does it have to navigation of physical environments? or virtuals ones work too?
I'm not convinced, as every open world game after Morrowind has had a marker or route mapped out for them in the HUD. I wouldn't know how to get from A to B in most games without it. I get that it's opt-in in most cases but still.
That said, the effects of video games on brain aging will become apparent in the coming decades.
Ballet and Tennis are the main counters to pesky-brain-plaque. Constantly flexing your internal navigation system sounds like it achieves the same thing by the sounds of this headline. [I did not read the article]
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.
I wonder if it's actually anything to do with mentally mapping digital areas per se, or if it's more to do with the fact that you're not engaging your senses in the same way as when you're moving around a physical space.
If I go to a new place, say a gas station, there's a specific route I took to get there. There's smells and sounds and sights that will be specific to that time and place. I feel like that will generate a memory that's much grittier for the brain to hold on to, than one where I've digitally moved through a place. When I jump around a Quake map, I know where I'm going, but there's no wind in my face and I'm actually sat in a chair.
Sure there's sounds and sights in digital spaces, but they don't smell like anything and you're not actually touching anything but your mouse and keyboard. And the sights and sounds are less textured than real life - repeating assets, limited number of sounds etc. You're not gonna be surprised by a new birdcall, or a sudden burst of smell when the gas station guy opens the grill.
Knowing how important smell alone is to memory, I wonder if what's actually happening is that you're mentally engaged in a pretty narrow way when gaming, and that that's not really the best way for a brain to operate for long stretches of your life.
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.
> 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.
I think this actually suffers from selection bias. To be a taxi driver in London is not just simply applying for for the job and trying it out. You have to pass a very difficult memory test to be a taxi driver in London.
So the study might be testing out people who have extremely good memories to begin with and might be less likely to suffer from Alzheimer’s genetically.
So I’m wondering if this would still be true if it was tested on taxi drivers in New York City.
But my other theory, if this is not true, is that because they are now seeing Alzheimer’s as being a problem of glucose transport , and Since using your memory uses energy in the brain, this would lower overall glucose in the brain and protect it from developing all Alzheimer’s.
Or maybe like I said before that these people who can pass these taxi driver test already have excellent glucose transport in the brain which enables them to memorize the streets of London so much easier.
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?
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.
Besides, the point is a good one. There are a lot of professions. If we glance at the underlying study [0] Figure 1 suggests that we'd probably expect to see an outlier or two in that mess just through chance, we're expecting a few p<0.01. Taxi drivers doing unusually well doesn't seem especially impressive in that light, especially since it is one of the professions that seem to die off rather young and we might expect one of those professions to do rather well on Alzheimers.
[0] https://www.bmj.com/content/387/bmj-2024-082194
It's not terrible to not make a good point, but it's not a good point. The not good points should not be ranked highly.
It turns out that there is a profession with a lowest risk of getting Alzheimer's (duh, one had to exist) and it looks like a slight outlier (it's the lowest, we'd expect that one to look like a slight outlier). As outliers go it isn't that impressive, it looks like it is part of a fairly boring distribution. We just plotted 400 data points on the graph, the 1/400 chance weird data point is going to look a little weird. We're actually just reading a lot into the fact that the 2nd data point in ambulance drivers which isn't all that convincing.
Not to knock the study, I'm sure it is a great study. Lots of science done. They do good graphs and all that. But the study appears to be telling me that Alzheimer's is random with respect to occupation and ideally don't spend so much time on the road if you want to live to see old age.
Adjusting for age, Alzheimers deaths were 1/100 for taxi drivers, and 1/60 for the general public. That's extremely significant. However you feel about the graphs means nothing compared to the actual numbers presented here.
> I'm sure it is a great study. Lots of science done. They do good graphs and all that.
Your choice to be dismissively anti-science helps to explain the bad point you're making.
What makes you think that is significant at all? Anytime you take a lot of small subsets of a large random sample you expect to find outliers that look a lot like this.
That is https://xkcd.com/882/ seems to better fix the data just as well.
The article (and apparently the researchers too) advances the idea there's a causal link here, even though one is not shown by the research. They go so far as to generally prescribe spatial reasoning training as a way to reduce Alzheimers risk.
You might be tired of hearing "correlation does not equal causation", but it needs to be said here.
Their argument doesn't show that at all though, they make an argument against an age bias when the article explicitly says age is being controlled for.
> Figure 1 suggests that we'd probably expect to see an outlier or two in that mess just through chance, we're expecting a few p<0.01.
That's a valid point, and a much better criticism than the one I'm calling out. That doesn't redeem the original comment though.
If a study found people who swim regularly are are less likely to get heart disease, that wouldn't be very surprising because know a lot about why people get heart disease. Therefore it would be valid to insist on more rigour for accepting (swimming => less heart disease) because the only use of that information is for health advice.
However even weak statistical correlations can be a valid lead for further research into Alzheimer's disease if they suggest where to look. You don't need to prove that signposts are correct in order to use them.
It's absolutely not worth publication with clickbait title and distorted description to the general public.
Then not closely enough? The study adjusts for age, which is the core of OP’s criticism.
maybe it would help this thread to have someone explain exactly how they control for age, if everyone in the range they want to study, is already dead.
What is the actual process to control for age? This comes up a lot, and the only response is "oh, well, we controlled for that", well exactly how?
Seriously, I'm curious.
//lot of downvotes, not a lot of anybody actually able to explain it.
From Article, the age question does seem sketchy.
"Although proportional mortality analyses do not provide information about the population at risk, with careful selection of controls and risk adjustment for factors that may affect competing risks (eg, age, sex, and social class), these values can still serve as a useful indicator of variations in disease frequency across different occupations.16 17"
It's really difficult (maybe not possible) to do that in these large retrospective studies. Shingles vaccine preventing dementia, GLP-1 drugs preventing just about everything, etc, etc. There are plenty of good faith critiques of this kind of work from actual medical researchers making essentially the same point as the OP.
Plausible scenario. Individuals predisposed to Alzheimer’s experience different mental sharpness from birth and this makes them enjoy taxi driving less (more intense than long-haul trucking), and so they pursue taxi driving as a career at lower rates. Under this scenario, driving has no effect, it just induces a selection bias.
I'm also a little concerned that the BMJ plot of risk adjusted mortality still shows a clear positive correlation with age at death, which I strongly suspect would turn out to be statistically significant. The adjustment does not appear to be correct, therefore, and while that might still preserve these odd findings, it's definitely not ideal.
The much better occupation, from the graph, is the third outlier -- mining and geological engineers. Life expectancy: 80.3, risk-adjusted mortality: 1.1%. Or, alternatively, economists are close too (80.6; 1.19%).
Aircraft pilots, btw, really were the opposite end of the scale (78.1; 2.3%), surprising enough to be noteworthy beyond a control (the BMJ article does discuss this a little, but seriously -- that's very surprising for a highly-educated profession).
Being mentally active (or physically active?) IIRC makes actual plaques both less likely, but also less detectable - a taxi driver can forget 90% of what they know and still not get diagnosed because they don't get lost on the way to the shops. Also they are often masters of small talk.
I would suspect this would eliminate a lot of the experiments participants, as only people who go for regular cognitive check-ups might be eligible?
I cannot imagine there would be many people left who'd be eligible. I can only think of 1 person that does it.. and he obviously does it for the pure satisfaction of acing those cognitive tests, and not because he is showing worrying amounts of decline in his mental faculties.
For example, the other day I wanted to figure out what’s the current state about whether gender equality causes measurable benefits for companies… and the studies are terrible. All of them. Most of them was about Norway, and almost all of them had a reference point in 2008, one of the largest economic crisis, and somehow most of them was even worse than this. They openly distorted statistics. Depending on what they wanted to achieve to one way or another. Even the most cited ones. It’s disgusting. The best ones could prove only that inequality is not inherent of economics, but social. But the agenda was different for them too, so they tried to lie something bigger, all the time, while this would be more than enough to support it.
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?
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.
(Unless people highly predisposed to dying in car accidents are also highly predisposed to mudering people who will have, but don’t yet have, Alzheimers. But that seems sufficiently unlikely for the purposes of this hypothetical.)
Jokes aside, the serious answer depends on whether the link is causative or merely collerative.
Is every case of dementia diagnosed accurately? Is there a difference between professions how likely their dementia is to be diagnosed accurately?
Is there a correlation between dying early and being pre-disposed to have developed Alzheimer if having lived longer? If there is, then the "correction" for age is not correct, because the correction assumes the fraction of the group that died early were equally likely as the rest of the group to develop the disease if they had not died early.
I don't know anything about Alzheimer but it doesn't seem unthinkable that the factors that cause people to die early also could also play a role in causing Alzheimer.
There is no reason to believe they have enough data to adjust for any of their controls. It looks to me like they plotted everything and then found the "outlier" which statistically we know will exist in a true random sample.
Delay your aging by using your brain a fuck ton, all the time, learning brand new things nowhere near anything you already know.
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.
Being intelligent doesn’t mean you still learn new things as you age. Using your brain doesn’t do anything, it’s using your brain in novel ways.
That companion is also bunk. Two entirely different diseases.
/s
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.
Language skills atrophy surprisingly fast.
I have no idea what the truth is here...
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.
So no indication they accounted for the expected lifespan of the profession.
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.
then don't post
They claim to control for these factors in the 5th paragraph of the article here. Which is a standard thing to do in these kind of studies.
So you're point is either not relevant or that they didn't control for age correctly?
https://www.bmj.com/content/387/bmj-2024-082194
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...
This is very true. In my PhD research, I managed to perfectly predict the placebo effect using a random forest. Now, this was actually due to sampling variance, and the finding went away when I averaged over splits.
I often wonder if I'd still been in academia when this happened, if I would have been able to resist the siren call of a Nature/Science paper (and the consequent career benefits).
'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/
Dan Olweus did several of them in the 70s and 80s, and fought to his dying day against programs which didn't have casual intervention studies backing them.
Also, older ones were exposed to a ton of cigarette smoke.
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.
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.
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.
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!"
"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."
Where? What country/ies?
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).
2. The original study didn't just study taxi drivers, but also ambulance drivers. I doubt that their life expectancy is that much lower.
Define "hard job". Carrying heavy objects?
Odd hours, sitting too much, inhaling too many exhaust fumes, having people yell at you if _they're_ late.
Sounds like a fairly hard job.
There are jobs stressful on the mind too - and some of them have very low "life expectancies".
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.
[0] https://www.youtube.com/watch?v=ur61kzXjvN8
There's a fantastic Tom Scott video on it https://www.youtube.com/watch?v=ZmWREtcDVBE
I am glad Uber plowed through various stupid regulations constraining supply to bring a service with drastically more supply.
What like safety checks?
London had a huge minicab system, which is very much not knowledge based. Addison lee also had internet booking of cabs way before uber, but with the advantage that cars were roadworthy and the drivers were safety vetted.
TFL came down hard on uber 1 for safety and 2 for clogging up the fucking roads and making busses slow. (see https://bsky.app/profile/garius.bsky.social for more info)
"which $generic_street_name? the one near covent garden, or the one near Bow?"
saves both time and money
Uber drivers are generally a joke compared to black cab drivers in pretty much every way
Stuff like "I'm your grandson, dadsnames kid" didn't parse at all, they said not to bring up shit like that so we didn't.
We had to move him into a house because he kept using his POW training to break out of the dementia ward. Pickpocketing keycards and shit, he was a badass till the end.
He told me he was so jealous of all this new computer stuff I get to play with. I think about that a lot this year
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.
If you get into a black cab in London and ask to be taken to any location, anywhere within 6 miles of Charing Cross, that driver will know immediately the right route to take without satnav. To get to that point they need to know 25,000 streets and many, many landmarks - statues, museums, galleries, restaurants, hotels, and so on.
I used to regularly drink with a cabbie in London, and he said that every time somebody got in the back his heart rate would rise, as he'd realise he's "on" and about to have to work out where to head from scratch. Within 30 seconds he'd have every step of the way worked out, down to which lanes at which intersections, no matter where in London he was or where he was going.
That's the thing that's likely going to reduce Alzheimer's.
It would also be interesting to look at sleep traces of cabbies.
https://en.wikipedia.org/wiki/Glymphatic_system
In the same way that you have code smell.
Granted, some use GPS, but most only really use it for pickup
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.
A number of the women in my wife's family have been diagnosed with Alzheimers. All of the women I know in her family also hate driving, because they find it very stressful.
It's plausible that people prone to Alzheimers are less likely to be comfortable driving.
Today this knowledge is arguably less useful.
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.
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.
Not at all, it's more like 6 hours if you're in a somewhat remote place, but most taxi trips are way smaller than that even in rural area anyway.
> Not to mention that the population in this usa countryside is already way lower then any population density in the whole of France.
I don't think it matters, as there are plenty of rural places in the US that still have a higher density than where I live.
> Operating a taxi corp there would simply be not viable on a financial term.
Probably not a taxi “corp”, but here taxis have always been independent businesses with one or two cabs an providing taxi service on an area of a few hundred of square kilometers (a radius of 50km or so around the "office" of the taxi driver). And a large fraction of the trips are not on demand, but upon reservation several days in advance (you know you'll need to go to a medical appointment to the city next month, or you need a ride to the train station later this week).
More than one time I got stuck somewhere and had to walk 4 hours home.
This was not the case everywhere. For instance, Ireland deregulated taxis in 2002, and service improved massively after that.
It's funny how many amazing tech developments are really just a reaction to the peculiar pathologies of American/SF culture.
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.
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.
Those jobs rely on navigation, not maps. Reading maps and navigating the real world are very, very different things.
The later point about zip codes with higher complexity is the same - these residents have to _navigate_ in more complex situations. How the author seems to be conflating that their personal job of staring at maps therefore protects them from Alheimers is very wishful thinking IMO.
Based on this data, I wouldn't be surprised if Google Maps has lead to a rise of Alzheimers.
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.
Their content publication history should be a good metric for establishing our future subjects and departed ones as engaging in above average gameplay for each specific genre.
I’ve always found it fascinating that I could recall essentially turn by turn navigation of WoW classic routes in which I spent countless hours. I’ve always thought about trying the memory palace technique and using those routes which would probably work well.
e.g with the potent use of marijuana that's present these days, excess drinking & lack of reading + dumbing down of population via use of llms.
Alzheimer's disease mortality among taxi and ambulance drivers (2024)
229 points, 4 months ago, 137 comments
https://news.ycombinator.com/item?id=47559481
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Taxi drivers offer a clue to Alzheimer's risk
127 points, Dec 2024, 109 comments
https://news.ycombinator.com/item?id=42502899
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Alzheimer's Mortality Lowest for Taxi, Ambulance Drivers
12 points, Dec 2024, 9 comments
https://news.ycombinator.com/item?id=42450455
> 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.
https://www.walkscore.com/MA/Boston
And the second thing: What about modern taxi drivers that rely almost exclusively on GPS?
https://pmc.ncbi.nlm.nih.gov/articles/PMC3920458/
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 ?
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?
When driving I either now the way or use maps, there is rarely any guesswork or active thinking involved, maybe running is helping but even there I sometimes run routes navigated by watch.
> roughly 1 in 100 compared with 1 in 60
I guess the broad population also rarely dies of Alzheimer’s?
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_.
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...
> 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
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.
That's plenty of time to be a full blown alcoholic.
Second rule - Got edge case? Got headline!
That said, the effects of video games on brain aging will become apparent in the coming decades.
If I go to a new place, say a gas station, there's a specific route I took to get there. There's smells and sounds and sights that will be specific to that time and place. I feel like that will generate a memory that's much grittier for the brain to hold on to, than one where I've digitally moved through a place. When I jump around a Quake map, I know where I'm going, but there's no wind in my face and I'm actually sat in a chair.
Sure there's sounds and sights in digital spaces, but they don't smell like anything and you're not actually touching anything but your mouse and keyboard. And the sights and sounds are less textured than real life - repeating assets, limited number of sounds etc. You're not gonna be surprised by a new birdcall, or a sudden burst of smell when the gas station guy opens the grill.
Knowing how important smell alone is to memory, I wonder if what's actually happening is that you're mentally engaged in a pretty narrow way when gaming, and that that's not really the best way for a brain to operate for long stretches of your life.
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.
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 mean, they should be. Games are for fun, not for work.
When in my car, I'm just dumbly following the map app. But on a bike, I'm still having to keep track of where I'm going and a route.
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.
They got rid of the exam in 2021, now you only need an navigation device in the vehicle.
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.
So the study might be testing out people who have extremely good memories to begin with and might be less likely to suffer from Alzheimer’s genetically.
So I’m wondering if this would still be true if it was tested on taxi drivers in New York City.
But my other theory, if this is not true, is that because they are now seeing Alzheimer’s as being a problem of glucose transport , and Since using your memory uses energy in the brain, this would lower overall glucose in the brain and protect it from developing all Alzheimer’s.
Or maybe like I said before that these people who can pass these taxi driver test already have excellent glucose transport in the brain which enables them to memorize the streets of London so much easier.
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.
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.
How about promoting spatial awareness and reasoning exercises (which is the actual suggestion of the article)?
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?