Alzheimer's disease mortality among taxi and ambulance drivers (2024) | Hacker News Reader

Alzheimer's disease mortality among taxi and ambulance drivers (2024)

bmj.com

229 pointsbookofjoe137 comments

The rate of fatality for Alzheimer’s among ambulance and taxi drivers is 3x lower than the general population. This is not observed in other transportation-related careers.

The connection is believed to be the spatial reasoning involved in routing. No causative link is suggested.

Except causation, what can the connection be? Some genes causing both spatial reasoning and suppressing Alz?

The taxi-driving Alz patients may overwhelmingly die of something that leads to physicians not listing Alz as a cause of death. If taxi driving is loaded in such a way that Alz presents significant challenges (eg loss of income), that could be the case.

But that's not a spatial reasoning connection. Also would include all other drivers.

One easy way to confirm this is to look at the impact of GPS on this + whether London taxi drivers get less frequent Alzheimer’s than other cities/countries that don’t have the same requirements and complexities.

What are some possibilities?

    1. Those with spatial reasoning are less likely to develop Alzheimers
    2. Ambo and Taxi drivers are less likely (for some reason) to develop Alzheimers AND their work leads them to develop good spatial reasoning.

Any others? One consideration is that those with jobs requiring long periods of concentration drink less. Among other things.

Social interaction while spatially reasoning also helps. (Social + cognitive load)

- Drivers with early symptoms of Alzheimer’s struggled to remain effective and changed profession

I had the same thought, but occupation on the birth certificate is the "usual" occupation the person held.

death certificate?

Just keeping you on your toes?

Assigned-cabbie-at-birth...

Isn't that the point? People whose cognitive abilities were already slowly declining would likely look for another job that was less demanding.

Sorry if I am misunderstanding you.

The implication is that if you spent 30yrs as an ambulance driver, followed by 10 years working retail, the death certificate will say "ambulance driver."

People with excess brain capacity are able to easily acquire spatial reasoning, and can (more) easily work/qualify for ambo and taxi jobs. Their excess brain capacity makes progressive brain damage more difficult to impact them before other causes of death.

I haven't read the article, but what if:

The problems arrizing from alzheimers are so problematic, that the cabdrivers / ambulance drivers drive themselves to death before they enter the stats as alzheimers patients?

A bit like the famous bullet holes in planes from ww2

Pure speculation here. Driving is a sedentary occupation which might increase the percentage of deaths attributable to a sedentary lifestyle, with consequent decrease for Alzheimers?

It's about hippocampal size, so people with a larger hippocampus are less likely to get alzheimers as it's a barrier, lots of studies scanning London cabbies brains and they have enlarged hippocampus - it's believed to give a barrier against alzheimers.

So spatial navigational ability is another risk factor/biomarker (along with blood pressure, smoking etc)

Ambulance drivers were close to medical professionals and got good, early diagnosis and care.

Taxi drivers were exposed to a wide variety of people who they conversed with, became aware of Alzheimer's symptoms and treatments and sought help early.

Off the top of my head.

That would normally make sense, but Alzheimer's treatments don't significantly prolong life. You'd also expect to see the same effect with other medical professionals.

Diagnosis helps put them into the data set. Even increased diagnosis would skew the statistics. Those that died of Alzheimer's and didn't know it, aren't in the study.

It seems like you could get into roles with a duty of care, logistic and deadline planning, social contact, etc.

And try to control with so many other non-transport occupations like nurses, therapists, hairdressers, air-traffic controllers, etc.

Ironically, the transport aspect reminds me of a prior correlation I read about for truck drivers and higher rates of colon cancer. There were speculative theories as to whether it was from the hours sitting or something like the chronic vibration.

I'm sure that the study accounted for this, but some fun ones

1. Ambo and Taxi drivers are vastly more likely than the general population to die in a collision before Alzheimers gets to them. 2. Even if you control out collisions, driving an Ambo and Taxi requires enough more memory and cognitive functioning to survive that people with early Alzheimer symptoms are significantly more likely to die in a collision, meaning you've controlled out a good chunk of ALzheimer victims in the process.

> The connection is believed to be the spatial reasoning involved in routing.

This is triggering me lol. I was a Paramedic for 10 years and 3 of those years were before GPS existed and we had these awful 900 page 5" thick things we had to wield on the fly called Map Books. It was part of our probation period testing and they would time us to pick out the routes reliably within a certain deadline or not graduate from being a probie.

While your partner drove to the call you'd put the book on your lap and flip to the big large grid which would tell you which map your location would be on (page 770), then you'd look up the street in the back appendix to get the coordinates for the specific house (P5, C2) and then find the cross street on another page (P5, C3), go to the grid and find the closest appropriate hospital for the purpose of the call (different ERs have different functions- for gunshots go to Highland, for amputations go to CalPac Davies, for heart attacks go to UCSF, etc) (page 815), the street location for that (A6, C4) and then make your route while flipping back and forth between all the pages while simultaneously telling your partner where to turn as you go.

When I went to a better ran company, dispatch would give us map page and grid coordinates over the radio when we got the call.

Within a few months you learn most of the neighborhoods and routes, and road hazards and preferences- for example if going to UCSF from the Peninsula take O'Shaughnessy because there's no traffic and is a smooth ride. And if you're going to Seton Hospital from 101 slow down around the turn on the on ramp onto 280 because there is a GIANT bump that will knock your partner in the back's head into the ceiling and not be comfortable for the patient on the gurney.

Map books were no fun but some of the dudes I worked with definitely became route-finding savants.

This is such a great anecdote, thanks for sharing!

>> for gunshots go to Highland, for amputations go to CalPac Davies, for heart attacks go to UCSF, etc

Oooft. My utmost respect. I could not do this job.

In a similar vein, to drive a black taxi in London you have to pass The Knowledge of London exam which requires becoming a human routing database for over twenty thousand streets and landmarks.

Made me think of this as well.

If I remember the story I read correctly, they just call it "The Knowledge". What a great name.

There is also a very good TV comedy-drama film of 1979 about some characters working towards passing the Knowledge exam. The film was, of course, called The Knowledge:

https://en.wikipedia.org/wiki/The_Knowledge_(film)

It's available on YouTube (potential geoblocking notwithstanding):

https://www.youtube.com/watch?v=oSAAB1ZmudY

Yep, if you see someone on a scooter with a clipboard attached to the handlebars it's quite likely to be someone studying for The Knowledge.

I know this from the "Up" series [1] from the late Michael Apted.

Tony got his "knowledge" around "21-Up" in the series, became a London cabby by "28-Up" [2].

[1] https://en.wikipedia.org/wiki/Up_(film_series)

[2] https://youtu.be/_rQ1V7m0Kfs?t=142

The Knowledge is exactly the first thing to get into my mind the moment I read the headline.

Amazing. Paper-based GPS before actual GPS was a thing.

Wait till you see the Honda Electro Gyrocator:

https://en.wikipedia.org/wiki/Electro_Gyrocator

And they are called maps. Wonderful stuff.

> Map books were no fun but some of the dudes I worked with definitely became route-finding savants.

Similar. I worked doing deliveries for an event company all over the greater NY area, based out of Queens. I usually rode jump-seat and spent a few years with a retired trucker who was such a savant. He could maneuver a truck through any tight/precarious situation with great precision and care. He could visit a location once and recall it next year, every year.

The most impressive was a full day gauntlet starting at 5 AM where he navigated starting in south queens NYC to a stop in Staten Island, then off to Jersey city, then up to Sleepy Hollow NY, then all the way to some Greek church deep in Suffolk county through the winding maze that is the north shore - no map, no gps.

The most scary situation was driving a smaller Isuzu cab-over box truck through Brooklyn on a hot summer day. We had no AC, windows down, headed along a narrow avenue under the elevated train tracks. A passing truck was a little too far - BOOM- a loud shattering glass and bang sound. Turns out that idiot hit his mirror violently into ours so hard it showered him directly in the face with shards of mirror. I only got hit with a few pieces in the arm and a bunch landed on my lap. He didn't flinch. He kept the truck strait while muttering "I've been waiting for that to happen again." He thankfully only had two small cuts on his face, nothing went into his eyes. We lucky passed an auto parts store and he was able to rig up something on the mirror bar, continued on and finished the route.

He was a real character and he always had a lot of fun and crazy road stories. That dude also taught me to drive a truck with air brakes which is also how I learned to drive a manual. In addition to showing me all the secret traffic avoidance and toll beating routes, he was a foodie and showed me a lot of interesting restaurants he'd stop at along our routes. He took me to the famous Wo Hop in Manhttan's China Town when you could just walk in and get a table (late 90's.) He parked the truck at an inactive construction site a block away and moved cones around it so we didn't get a ticket. That character knew all the tricks :-)

Hah. My father has similar stories from his time as a paramedic. There were some transitions from one page to another that were considered unusually difficult, and during training they would find a way to force the rookie map-book reader to handle these transitions. Bonus points if they could handle the situation when the route continually straddled a page boundary!

They also, of course, knew which streets had been re-marked as one way and such since the map book was published, so they got the rookie into tricky positions where the world conflicted with the map, forcing them to spend only part of the time with their nose in the book.

Will we see a drop in alzheimers when the open world gaming population reaches that age? I mean, I can not just navigate my city, but multiple worlds!

even with one functioning eye! because you're used to navigate by looking at a 2d projection on a screen

And/or will we see an increase in Alzheimer's disease amongst Google-Maps dependent users? Maybe we will see a bimodal split in both directions.

Yeah, basically Waze is causing dementia

Not sure about Waze, but the combination of AI + TikTok/shorts/etc sounds like “not great” for long term brain health.

Indeed. My comment about Google Maps (and Waze, etc.) exacerbating Alzheimer's was mostly in jest and an exaggeration, but I'm absolutely certain that there is a statistically significant proportion of society whose current overuse of "AI" chatbots and short video consumption will result in cognitive deterioration if it continues at their current rate.

To be clear, I'm not implying that usage of LLMs or viewing potentially unlimited video shorts is necessarily bad, nor could I guess the threshold from which doing these things becomes cognitively damaging in the long term. All I'm saying is that such a threshold exists and some people in society are surpassing it.

There's a paper on it:

"Video gaming, but not reliance on GPS, is associated with spatial navigation" paper shows there was a significant association between self-reported weekly hours of video gaming and wayfinding performance.

https://www.sciencedirect.com/science/article/pii/S027249442...

Tested with Sea Hero Quest

With the open world™ minimap and objective markers on the corner of the screen? I suspect not :)

I’m not sure because in many modern open world games you are just like a Uber driver following GPS from checkpoint to checkpoint. It would with old school games that relied on memorizing the world and had minimal or even no map indications.

I feel like a dark souls game has a similar learning pattern where you need to memorize the move sets of bosses. It taps into that dynamic pattern recognition that traffic would cause for taxi drivers

DayZ is another one because there is no in-game GPS. You have to use maps and compasses to figure your route and many people can spot an exact area on the massive map by a picture of a bush

Both are also very social occupations, talking with multiple strangers every day.

The main question that comes up when I see a study like this is if they were able to take the same hypothesis and replicate it on another dataset in a different locale. For instance, presumably you could run the same study on UK data. Would we see the same results?

This kind of replication would make the findings much more convincing.

A causal link is easy to imagine. An Alzheimer's onset makes one unfit to work as an ambulance driver, they switch to a less demanding job. When, years later, the person dies, the death is not counted towards ambulance drivers.

> death certificates included a field for reported usual occupation (the occupation in which the decedent spent most of their working life), generally completed by a funeral director with help from the decedent’s informant

I’ve always been horrible at spatial reasoning. If I take two right turns and then a left, I have no idea where anything is. I’ve anecdotally always found a correlation between “cool” people and sound spatial reasoning. I’ll probably get Alzheimer’s when I’m 35.

The biggest weakness in the study is that Taxi and ambulance drivers in the dataset died around 64 to 67, versus 74 for other occupations [0]. If Alzheimer's is much more likely to show up later, then lower Alzheimer's related death rates among Taxi and ambulance drivers may reflect earlier mortality rather than any effect from the job.

[0] https://www.sciencemediacentre.org/expert-reaction-to-study-...

If you read it, one of the first things they discuss is methodology for adjusting for age at death as it relates to Alzheimer's mortality, citing exactly this objection. I'm not a statistician and I don't know if their methodology is solid or not, but it's been addressed.

NB: <https://news.ycombinator.com/item?id=47390621>

One of the first signs that a somebody has Alzheimer's is that they'll get lost. E.g., they've been attending church on Thursdays nights at the same chapel for 15 years, but suddenly they forgot how to get home after a recent service. Part of the reason for the findings in the current study is that people quit those professions when they feel themselves starting to struggle.

Is the profession cached in the data when they leave the job? And does the data attribute 2 entries for someone with 2 careers. That’s the question I think

They explain it in the article. Someone, often the funeral director filling out the death certificate, asks what the deceased did for most of their working life.

I’m a little skeptical of the category “ambulance drivers; not emergency medical technicians” as reliably coded, because people will often say so-and-so “drove an ambulance” when they were actually an EMT or paramedic. But it’s also not clear to me that would invalidate the findings.

Yeah my mom would slowly forget how to get to my house, it was sad she would always try but just not quite get it... She eventual died of Alzheimer's a some years later...

A friend of my wife's suffered a stroke recently. One of the first signs something was really wrong was she took a circuitous route around town to get home, then called her husband and said "I'm lost, I don't know where I am". She was parked in her own driveway.

It seems a lot of people already know that. I remember their's a claim that Taxi drivers hipocampus is larger than average people. A memory method called "Memory palace" or "Method of Loci" exists for 2 thousand years exploiting human's navigation capability.

https://en.wikipedia.org/wiki/Method_of_loci

This series of graphs https://www.bmj.com/content/bmj/387/bmj-2024-082194/F1.large... shows that whilst those two professions are at the bottom of the distribution they are not particularly outlying and cherry picking of those professions has occurred. The statistical analysis should have adjusted for picking the best 2 occupations of the 443 in the study. That would likely show very little statistical significance.

I immediately go to these two thoughts:

- Is significant life-long usage of real-time mental spatial navigation protective?

- Are those who end up in these positions self-selected for better than average real-time mental spatial navigation and that above average performance correlates with protection against Alzheimer's.

I think your 2nd point is less likely.

Anecdotal, but I've spoken with many taxi and ride-share drivers, and my impression is that their decision to seek out and continue that line of work is almost always driven by outside economic considerations. I've never heard someone base their decision on their ability to perform the job.

> I've never heard someone base their decision on their ability to perform the job.

That they’re consciously aware of

Exactly - I'm thinking the bad spatial navigators have a higher probability of washing out of driving and pursue some other career. They may not say "I'm bad at figuring out where I am", but the economics of the job are just a little bit worse for these people.

There's a big difference with being a driver now, though, compared to having had it as a career and being part of this study. They did it before gps.

100%.

I would imagine the combo of spatial reasoning and mapping plus social stimulation could be a reason. You could also argue both are regularly training reflexes and fine motor movement.

Or could be there some weird variable that's unaccounted for ? Do taxi drivers and ambulance drivers for some reason have more regular sleep patterns ? We know that is definitely helpful for Alzheimer's

Your reasons listed under a HN comment are more plausible than those listed by who worked on this subject for years. I find it funny and admiring.

Taxi drivers and ambulance drivers seem like two jobs that would have less regular sleep patterns, TBH.

That's what I was possibly thinking as well. Or it could be that their jobs are stimulating in a way that makes them tired in a way that promotes quality sleep.

Or maybe they just get great at napping on the job !

> Setting: Use of death certificates from the National Vital Statistics System in the United States, which were linked to occupation, 1 January 2020-31 December 2022.

Doesn't this mean that if you get Alzheimer's and as such are unable to work, that it is quite unlikely you would show up as a taxi/ambulance driver in this study?

Such studies need to account for transfers between groups, but rarely seem to do so (I did not read the complete paper, please correct me as necessary).

they spend almost a whole page addressing this.

... Alzheimer’s disease symptoms typically develop after patients’ working years, with only 5-10% of cases occurring in people younger than 65 years (early onset).11 14 While subtle symptoms could develop earlier, they would still most likely be after a person had worked long enough to deem the occupation to be a so-called usual occupation ...

Yes I saw someone say as much in other comments. My suspicion that transfers were not accounted for because the employment was a snapshot in time between 2 years was definitely wrong.

"What the funeral director deemed/was instructed to record as 'career'" is still somewhat limited, but is plausibly good.

The premise for this research question is related in part to work from Dr. Eleanor Maguire (who I just learned died last year at only 55) and her team on hippocampal anatomy and careers involving spatial navigation, including taxi drivers. A connection that may be of interest to HN readers: Demis Hassabis was one of Maguire's doctoral students, although he does not appear to have worked on the project most relevant to this study.

>What It Takes to Pass “the Knowledge,” the “Insanely Hard” Exam to Become a London Taxicab Driver

https://www.openculture.com/2024/08/what-it-takes-to-pass-th...

>Learn the Knowledge of London

https://tfl.gov.uk/info-for/taxis-and-private-hire/licensing...

>The Knowledge, London’s Legendary Taxi-Driver Test, Puts Up a Fight in the Age of GPS (2014) — "Its rigors have been likened to those required to earn a degree in law or medicine"

https://archive.ph/cWFxd

So why not bus drivers? Supposedly because their routes are fixed?

Maybe them too, to some extent. Have they been studied?

Friend of mine is an airline pilot and when she was doing short flights, going around several EU capitals per day she said "it's like driving a bus". You fly from A -> B -> C -> D -> A. And start over again the next day. She wasn't a huge fan.

>They booked a flight — and got a bus

https://wapo.st/3Q41RX9

Would love to see a study looking at people who spend significant time in video games that require spatial navigation.

That could even be a form of therapy after diagnosis (which seems to become easier with biomarkers).

Vsauce did a video about how League of Legends can affect spatial navigation and the brain: https://www.youtube.com/watch?v=1RHsAUyFCAM It seemed a bit odd to me since LoL isn't especially navigation-heavy, but Michael from Vsauce later confirmed he was actually playing LoL (they just weren't allowed to name it or show it directly - https://www.reddit.com/r/vsauce/comments/7igkve/what_game_do...).

Hmm, never played LoL myself but is keeping track of were the opposing hero can be given were you last saw them a big part of the strategy?

That description is accurate, but that's more of an attention management problem then of a navigation problem. You have to infer information about opponent positioning based on partial information, while also moving your character with repeated clicks, each click requiring precision (and more of your attention). It's more like poker in real-time with timers than to remembering a whole city infrastructure or planning a full route.

If LoL trained you for ambulance work, the world would look something like: there are 5 hospitals, 3 patients, 15 roads; a hospital inspector goes from hospital to hospital, panicked hospital managers open that hospital for 5 hours after inspector is about to arrive; you have another ambulance friend that tells you from time to time info about last inspector location or how panicked the managers looked; infer open hospitals and inspector location such that your patient survives, while you also have to maintain a high Candy Crush score on your phone non-stop.

Only for high level strategy I would say. Generally you have to process lots of visual information and decide/act fast according to it.

There is a small mini-map where all heroes currently visible on the map are shown. A high level player would for example reason: "I saw the enemy carry farming there 30 seconds ago, so right now he is likely in that area".

Look at https://seaheroquest.com/papers this is a game I designed and developed that links spatial performance to population scale navigation changes across 4.3m people.

My first reaction to the title was: "duh, selection/survivorship bias" but their counter is pretty solid:

> Firstly and perhaps most importantly, selection bias is possible because individuals who are at higher risk of developing Alzheimer’s disease may be less likely to enter or remain in memory intensive driving occupations such as taxi and ambulance driving. This could mean that the lower Alzheimer’s disease mortality observed in these occupations is not due to the protective effect of the job itself but rather because those prone to the disease may have self-selected out of such roles. However, Alzheimer’s disease symptoms typically develop after patients’ working years, with only 5-10% of cases occurring in people younger than 65 years (early onset).1114 While subtle symptoms could develop earlier, they would still most likely be after a person had worked long enough to deem the occupation to be a so-called usual occupation, suggesting against substantial attrition from navigational jobs due to development of Alzheimer’s disease. Moreover, even if lifelong taxi driving selects for individuals with strong spatial processing, our findings would still suggest an interesting link between spatial processing skills and risk of Alzheimer’s disease.

I'm not sure if this relates to how the brain stores/process navigation information, or how does it uses/manages that information "in-motion."

For example, I know my city very well and can navigate through it with no GPS help.

But, according this study, ship captains, whom uses more complex navigation and spatial mechanisms, are amongst the most affected ones, maybe this is actually about "decision-making."

When I was growing up, we had these big books called Thomas Brothers Guides. I remember giving laminated versions as gifts - one of the best gifts you could give.

I worked as an EMT for about 4 months and for the first few weeks had to drive around while the Paramedic (we rode EMT/Paramedic pairs) quizzed me about "if we got a call at XYZ, how would you get there"

Talk about vivid dreams every night.

I played (vibe coded) around with the CDC records and the results look easily reproducible. Here it is in my vibe gallery: https://suvakov.github.io/vibes/AlzheimerMortalityByOccupati...

Pointing again to the idea that this disease is triggered by bacteria, at least in some cases [1].

By bacteria or another microorganism that is alive (not a virus). There is a growing suspicion that oral bacteria is related with Alzheimer somehow.

Taxi and ambulance drivers have one thing in common with all the other drivers: they live behind an habitacle filter most of the time. But they have also one particular thing in common that truck drivers and car owners don't have.

They disinfect the car with alcohol after each customer.

[1] This does not mean that other causes like chemicals or pollutants known to damage the nervous system couldn't trigger it also.

I was really expecting this to be higher not lower due to factors like particulate inhalation from exhaust/brake dust/tire particles. Also there's a lot of sedentary-type problems you get while taxi driving like bad diet habits that are not conducive to brain health.

Dunno, did taxi driving for a few years. Mostly suburban for a small fleet, not gigging. I'm thinking newer drivers that rely on smartphones for navigation won't get the same benefit.

I seem to recall that at least some populations of taxi driver they have exams like The Knowledge (https://london-taxi.co.uk/the-knowledge/) where changes in structures of the brain can be measured after learning it.

I was thinking the same thing, about the tire particles and sedentary problems. It's really true the what you do for your daily work over many years shapes your body.

Probably die early from lung or bladder cancer but you won't get alzheimer's!

Ambulance drivers, truckers, delivery drivers and taxi drivers are more likely to get bladder cancer, most likely from holding in urine but also probably from diesel fumes and pathogens from road dust particulate matter.

My shitty ambo company sold our sleeping quarters as revenge when we tried to unionize and so we would have to sleep in the rig and would run the engine to keep warm, I am sure I will meet an early death from sucking in all those diesel fumes over night shifts.

I am slowly learning how to navigate useing OSM on my phone, haveing never used guggle or GPS, but then bieng unable to buy replacement paper maps, the small screen format is frustrating... I have driven courier in a mostly shook 1 ton ford, though it did have a built race motor and a 5 speed, and would snap and bark on the down shift,setting off every car alarm on the narrow steets, doing nothing for the mental states of all those people bieng dutifuly parinoid about there cars. It is the last, the low level persistant unresolved stress, coupled with never going out and blowing off steam, or finding some fundamental satiation, or even true physical and mental exhaustion, and a well earned rest.

So let's say there's a causative link (see other comments here for why this may not be the case), it would take a lifetime of daily complex spatial navigation for several hours every day to significantly reduce Alzheimer's disease risk, and it's still not guaranteed. If there's a linear dose response (a big if) it would still require hours per week for decades for a more modest impact.

That seems unattainable for anyone at all.

Man, Alzheimer's disease sucks. We need more investment and more research into this horrible illness.

Personally I'm curious about the impact of super-early diagnosis, decades before symptoms, and interventions that maximally slow progress.

See:

https://www.nih.gov/news-events/nih-research-matters/blood-t...

https://www.nature.com/articles/d41586-025-02928-6

https://archive.ph/bDYEr

https://corporate.dukehealth.org/news/nasal-swab-test-spots-...

I wonder what a similar study will look like for those who enjoy competitive online gaming into their old age. If the microplastics do not get to our brain first, of course.

My guess: On the left of the mortality curve are those who play Minecraft without mods and not using maps, and on the very right edge are those who use modded Minecraft with minimap.

I wonder what about gta players. And does playing GTA mainly in taxi count in

What have you been doing to prevent / reduce microplastics?

Isn't Alzheimer manifesting itself at an old age? Maybe taxi and ambulance drivers aren't too old? Maybe we find the same if we analyze jet fighter pilots?

Here, ambulance drivers are often ex-firefighters and vice versa, and both tend to be in good physical shape. Ship and airliner captains on the other hand are often older and in less than stellar physical condition.

My hypothesis is that it's either age, physical condition or both.

I assume that was a generation that didn’t use Google Maps.

At my most recent EMS job ("ambulance driver" is considered insulting), the younger people couldn't navigate anywhere without mapping it. Some of them brought up being amazed that I could get to every hospital in our area from pretty much anywhere without having to bring it up on my phone (random houses and nursing homes were a different story).

The funny thing is this study only looked at non-EMT ambulance drivers - i.e. those true ambulance drivers!

Statistically you'd expect some "random" samplings of the population to show significant deviations from the mean just by chance.

Roll enough different sets of dice and you'd expect some to end up being all sixes - that doesn't mean that set is rigged. Yeah, they're the ones you'd do further tests on, but it's not evidence in itself.

If the amount of individuals in your sample is large enough, it shouldn't be the case.

Relevant XKCD: 882

But that's why you do multiple testing correction

Does the data reject the null hypothesis? If you group people into hundreds of groups (occupations) and measure something (Alzheimer's rate) variance ensures that the means of the measurements will vary. Some groups will have low means other will have high means. The distributions may be equal but due to random chance there will be outliers.

If we've got data for 400 occupations, and studying the two obvious outliers (as shown in Fig 1), isn't this p-hacking? Not saying malice is involved, but with so many occupations, the statistical aberration would be not to find outliers that spuriously pass statistical significance testing.

p is not p-hacking. p-hacking is when instead of making a hypothesis and then looking for a correlation instead you look at the data and see if there are any correlations to be found. The problem with the second is if there are lots of possibilities it's much more likely that you will find a spurious correlation. That happens because the sample distribution is not the population distribution. And in fact in complicated data sets it's more likely that if you look at everything that you'll find spurious correlations than not. In social sciences these days people often register their hypothesis before running the study to prevent p-hacking and reduce the possibility of spurious correlation.

>Blood test predicts start of Alzheimer’s disease symptoms

https://www.nih.gov/news-events/nih-research-matters/blood-t...

Would be interesting to see whether spatial reasoning from gaming shows the same association.

This is indeed interesting because rotating 2D screen is not necessarily the same type of brain processing as experiencing things fly around you. Even VR is not necessarily the same, because knowing you're safe may be different from taking the situation seriously. Could be same, could be completely different.

But the first massively popular 3D games started end of 90s which means Alzheimer cases for them will pop up only around 2060 or later (average onset year 75 minus being 15 years kid during 90s).

Besides safety, there is also the cognitive complexity angle.

Plus, digital environments are explicitly designed to be engaging: authors are putting intentional thought into making the virtual space easy to navigate so that the player doesn't get frustrated and go do something else.

Meanwhile, the physical world is something we're pretty much stuck in, and material spaces tend to be optimized not so much to be engaging to navigate and explore - more to be comfortable to inhabit, etc.

Besides, physical spaces - e.g. cities - tend to be iteratively developed over generations, bearing the hallmarks of many different thinking minds, and not optimized for any one particular user flow.

I cannot navigate for to save my life, if this ends up be causal i'm so screwed

If I may suggest, my wife and I are advanced in age. When we were young, like everyone else, we used maps and the travel atlases as we roamed around the US. I was a semi-expert at maps because of my Dad's guidance as a kid. My wife, on the other hand, didn't know east from west.

So, before every trip, the night before we left we would study a map, always stressing the direction of north and monitoring the sun's position. To her joy she became an excellent co-pilot, soon surpassing my map skills! Now, of course, there's GPS, which we both love, but agree isn't as much fun as maps. (We still carry an atlas in the car for a backup.)

From the graphs it looks like ambulance drivers and taxi drivers died much younger than everyone else. Hence less death from Alzheimer (a disease famous for happening mostly with old age), so case closed?

I am afraid, there are far bigger confounders than that (which they supposedly correct for): you absolutely cannot be a taxi driver if you experience short term memory loss. So those people may have changed profession at a faster rate than say kindergarden teachers or bakers. Tbf. GPS somewhat changed that but with GPS, the spatial information thing makes less sense.

That's interesting. It's one of a few studies that supports a mental functioning, if it's lifelong and of specific type, prevents nerve cell degeneration and dying. If the theory that mind inactivity causes dementia is true, it will revolutionise it's prevention with lifelong adult training. AI could help immensely in this field keeping the community mentally occupied. I am waiting for a solid study measuring that a stress free group (either due to personal or professional status) beats all the stressful ones. We know it happens but it's nice to have evidence. Which group has obviously less stress today?

> Of 8 972 221 people who had died with occupational information, 3.88% (348 328) had Alzheimer’s disease listed as a cause of death.

A sample of a sample of a sample...

That's a pretty positive spin on this statistic that ambulance drivers and taxi drivers die much younger than many other professions

Smug ignorance is the most exhausting kind.

The way I read this is spatial reasoning takes may be one of the more effective methods of bolstering cognitive reserve.

The answer to this is Life Expectancy;

Ambulance Drivers: The mean age at death is approximately 64.2 years.

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 between 75 and 84 years.

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.

if you had signs of dementia you maybe quicker being found out in these professions because you'd take too much time/get lost etc. Which means you are not in the taxi/ambulance profession when you have dementia. So there is survivor bias in this test?

I wonder if the benefit is conferred by navigating around open world videogames for n hours per day.

That's interesting, all of that Spatial Processing and critical thinking keeps the brain juicy.

Let's hope flying cross country using pilotage has a similar benefit, if one truly exists.

Interesting cause that oxidative stress is particularly lower for them.

What about other driving occupations?

- fire, police, postal, long haul trucks

related - Indian food contains turmeric (curcumin) and indians don't get alzheimer's as much.

“Use the KNOWLEDGE Luke, always”

Hey! Its time to make some crazy money! Are you ready? Here we go!

https://en.wikipedia.org/wiki/Crazy_Taxi

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