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

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.

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-...

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.

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

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."

> 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).

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

>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

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.

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.

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

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

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.

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.

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).

>Blood test predicts start of Alzheimer’s disease symptoms

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

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.

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

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.

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 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.

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

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

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?

Interesting cause that oxidative stress is particularly lower for them.

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.

What about other driving occupations?

- fire, police, postal, long haul trucks

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

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

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

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?

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

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.

> 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...

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.

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.

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

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?

“Use the KNOWLEDGE Luke, always”

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

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.

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

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.

Talk about vivid dreams every night.

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

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

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

“Use the KNOWLEDGE Luke, always”

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.

> 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.

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!

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.

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

[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.

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...

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

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.

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.

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...).

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

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.

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

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.

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 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.

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?

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).

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).

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.

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

I think your 2nd point is less likely.

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.

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

That they’re consciously aware of

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...

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 !

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?

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

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!

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?

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.

Smug ignorance is the most exhausting kind.

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.

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

That they’re consciously aware of

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

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.

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

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.

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.

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!

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.

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

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.

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

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.

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

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

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.

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.