[HN Gopher] Taxi drivers offer a clue to Alzheimer's risk
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       Taxi drivers offer a clue to Alzheimer's risk
        
       Author : julienchastang
       Score  : 61 points
       Date   : 2024-12-24 16:23 UTC (3 days ago)
        
 (HTM) web link (www.wsj.com)
 (TXT) w3m dump (www.wsj.com)
        
       | neonate wrote:
       | https://archive.ph/9oqkn
        
       | iJohnDoe wrote:
       | Maze Runner premise? Stimulate brain activity.
        
       | andsoitis wrote:
       | > Taxi drivers may have a lower risk of developing Alzheimer's
       | because they are constantly using navigational and spatial
       | processing.
       | 
       | It would be interesting to know whether certain kinds of video
       | game play have a similar effect. On the one hand, you don't do it
       | for 8+ hours a day every day (unlike cab drivers), but on the
       | other hand, there might be a much higher volume of spatial and
       | navigational decisions packed per minute in certain games.
        
         | portaouflop wrote:
         | You would be surprised how many people pack in more than 10
         | hours of Fortnite or similar games.
         | 
         | On the other hand reality is much more complex than any game,
         | so I am not sure if these nav decisions are equivalent.
        
           | justin66 wrote:
           | > On the other hand reality is much more complex than any
           | game
           | 
           | Untrue. A Taxi driver won't have to worry about elevation
           | changes much at all. Zooming around a computer-generated
           | space in a game might have a lot of that.
        
         | ajuc wrote:
         | As long as you disable the minimap in game. Which is the
         | correct way to play open world games anyway. Other ways you
         | look at the arrow instead of looking at the environment.
        
         | chrisbrandow wrote:
         | I'm not sure it's equivalent to building a mental map of a 3D
         | space. It certainly might be, but I can also imagine that it
         | might have key differences.
        
       | apsec112 wrote:
       | Here's a link to the actual study, which is very readable:
       | 
       | https://www.bmj.com/content/387/bmj-2024-082194
        
       | wigster wrote:
       | so - switch off your sat nav
        
       | m3kw9 wrote:
       | Not sure how that compares to era where most people didn't use
       | google maps, but if you use google maps, you are using some part
       | of your brain less especially memorizing or trying to reverse a
       | route from memory. Or that if you can't remember very well, you
       | wouldn't last long as a taxi driver(survivor ship bias)
        
       | zerr wrote:
       | Does navigating spaghetti code count as well?
        
         | anadem wrote:
         | I think navigating code definitely has a relationship to
         | navigating meatspace, and the ability to internalize a view of
         | the code space makes for a good programmer.
         | 
         | I'm long retired now, but attribute a lot of my programming
         | ability to having had very poor sight in early childhood thus
         | having to keep a mental map of my surroundings.
        
         | fn-mote wrote:
         | Navigating it? How about _writing_ it?
        
       | throw0101d wrote:
       | > _Taxi drivers may have a lower risk of developing Alzheimer's
       | because they are constantly using navigational and spatial
       | processing._
       | 
       | A good reason to not use GPS/GNSS apps too much.
       | 
       | Unless it's going to a location that's completely unfamiliar, I
       | try to only check for red zones before I leave, and then use my
       | familiarity of my city to get to my destination: know my starting
       | point, know a major intersection near the destination, and avoid
       | known-bad locations in between. If I get lost I can always pull
       | out the app to re-orient.
        
         | Aloha wrote:
         | Agreed - I use GPS to do the initial pathfinding - in much the
         | same way I'd use a paper map in the old days.
         | 
         | It's part of why I have a good sense of direction.
        
         | tzs wrote:
         | Even when using it to go someplace unfamiliar you can pay
         | attention and try to spot features of the area that you can use
         | later to orient yourself if you ever want to navigate there
         | again but without GPS.
         | 
         | I wonder if that would sufficiently engage your navigation and
         | spatial processing to give some of the same benefits the study
         | found?
        
       | j7ake wrote:
       | A whole generation now uses navigation, is the prediction that
       | there will be an increase in Alzheimer's in this new generation
       | due to reduced navigational processing?
        
         | _3u10 wrote:
         | Alzheimer's is heart disease for the brain. Some even say it's
         | a form of diabetes. Using your brain less definitely increases
         | risk.
        
       | aeternum wrote:
       | Very flawed study. Looked at profession based on death
       | certificate which is most recent profession.
       | 
       | Those with Alzheimer's likely won't last long as taxi drivers so
       | they find a new profession. And voila their profession from the
       | viewpoint of this study is no longer taxi driver.
       | 
       | Much surprise that our lauded peer review process didn't catch
       | this.
        
         | j45 wrote:
         | Does most recent profession have more impact than the
         | profession with most years?
         | 
         | It's likely that using ones brain on average more while driving
         | may be a contributing factor. Wayfinding can be a neurally
         | intense activity.
        
         | jvanderbot wrote:
         | Very specious comment. From the actual article:
         | 
         | > Additionally, 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.
         | 
         | So, not as closed-case as you suggest.
         | 
         | Slam-dunking on studies is a top-tier trope on HN. All studies
         | are flawed, but some are useful.
        
           | atoav wrote:
           | I'd love it if the slam-dunkers occasionally went out and
           | made their own, better, studies to show the world how to do
           | it correctly.
        
           | theoreticalmal wrote:
           | Brutal
        
         | theoreticalmal wrote:
         | How confident do you have to be to make a comment like this?
         | Not only point out a problem, but make a snarky comment about
         | the larger system in top of it. What happens to your psyche if
         | you're wrong? Is the risk of being wrong outweighed by the
         | emotional boost of being right? Did you even consider you might
         | be wrong? I'm genuinely curious
        
           | lupire wrote:
           | After making a bad comment, don't come back to check replies.
        
         | apsec112 wrote:
         | The study doesn't show the same effect for airline pilots, who
         | definitely can't work while having Alzheimer's.
         | 
         | https://www.bmj.com/content/387/bmj-2024-082194
        
       | bgun wrote:
       | This is basic "mind palace" theory, no? Human memory is linked to
       | navigation; the more you associate memories with navigable
       | places, the stronger your memories will remain.
        
         | etrautmann wrote:
         | I have distinct memories as a kid of mapping things into
         | abstract 3d spaces. The number line in my head is a weird 3D
         | thing I still visually navigate whenever I think about numbers.
         | 
         | what's weird is that even while I still use my representations
         | formed as a kid, I don't seem to make new ones when I learn new
         | info, which makes remembering things much harder.
        
           | BjoernKW wrote:
           | > I have distinct memories as a kid of mapping things into
           | abstract 3d spaces. The number line in my head is a weird 3D
           | thing I still visually navigate whenever I think about
           | numbers.
           | 
           | I do the exact same thing! I wrote a blog post about how I
           | visualise numbers: https://bjoernkw.com/2022/01/02/i-see-
           | numbers/
           | 
           | It's a specific type of synaesthesia called "time-space
           | synaesthesia".
        
           | toss1 wrote:
           | >> I still use my representations formed as a kid, I don't
           | seem to make new ones when I learn new info
           | 
           | Very interesting; why do you think that is?
        
       | phillypham wrote:
       | I wonder if this also applies to people that live urban
       | environments that don't drive and have to navigate walking or
       | using the subway.
       | 
       | From my anecdotal evidence, it does seem that the average elderly
       | person in NYC is way more active and social than an elderly
       | person in the suburbs. But of course, it could be that people
       | that live in cities self-select.
        
         | netsharc wrote:
         | The fact that they have physical exercise (i.e. walking)
         | probably contributes a lot..
        
         | nine_k wrote:
         | They sort of self-select by the ability to earn enough to
         | afford living in a city like NYC. There's enough low-income
         | n-th generation inhabitants though to form a control group.
        
           | noduerme wrote:
           | Is there a correlation between income and incidence of
           | alzheimers? I wasn't aware of one.
        
             | dgfitz wrote:
             | The more money you have, the longer you live?
        
               | noduerme wrote:
               | Yes but I'm not talking about quantity of older people in
               | total, I'm talking about what percentage of them get a
               | disease.
               | 
               | With cancer, which is also more likely the older you get,
               | studies show that the chances of dying from it are about
               | 12% higher in the poorest counties than wealthier
               | counties in the US. That is _despite_ people in those
               | counties having a shorter lifespan from all other things
               | as well.
               | 
               | So my question in response to the parent's throwaway
               | class warfare riff was: Given two people who survive to
               | the same age, let's say 80, is one more likely to get
               | Alzheimers than the other based on income? The article
               | here would suggest otherwise, given that taxi drivers and
               | ambulance drivers are among the least well compensated
               | workers and yet strangely have _1 /3rd the rate of
               | Alzheimers_.
               | 
               | [0] https://www.cancer.gov/news-events/cancer-currents-
               | blog/2020...
        
         | skybrian wrote:
         | Even among people who live in NYC, the elderly people who are
         | outside going for walks and taking public transport are going
         | to be healthier. If they're sicker or weaker, they would be
         | more likely to take a cab or stay indoors and have things
         | delivered.
        
           | eduction wrote:
           | If they're sicker or weaker, they would be more likely to
           | leave the city.
           | 
           | It is a difficult place for anyone, but especially for those
           | with trouble climbing lots of stairs, handling icy surfaces,
           | repeatedly shedding and putting on clothes, etc.
           | 
           | Or who are too old to sustain the illusion that their income
           | is on an upward trajectory, and the current difficulties thus
           | temporary.
        
         | hindsightbias wrote:
         | What about navigating all those Walmarts and parking lots?
        
       | byyoung3 wrote:
       | also probably higher rates of social interaction
        
       | ShakataGaNai wrote:
       | When I read these headlines I wonder "Causation? Correlation?".
       | Maybe it's addressed in the study but.....
       | 
       | Is it that navigating with you brain is good to prevent
       | Alzheimers? Or are you just more likely to die from something
       | else as a cabbie. Statically speaking your more likely to die,
       | than average, from a traffic related accident. Maybe the all the
       | fumes cause something else terrible that kills you, etc.
       | 
       | It does seem logical to me that using your brain more could help
       | offset these dementia related diseases. But it also seems like if
       | that made a huge difference, we'd see statistically vastly more
       | alzheimers in "low thought" jobs like retail cashiers and people
       | who don't work/retire early vs say... collegiate professors.
        
         | lupire wrote:
         | May be a simple as being poor and not retiring makes you less
         | likely to develop Alzheimer's.
        
         | chrisbrandow wrote:
         | The correlation alone provides evidence of something worth
         | pursuing and understanding.
         | 
         | They do have some possible causation when considering
         | hippocampus development observed in taxi drivers in other
         | studies.
        
         | apsec112 wrote:
         | They adjust for overall lifespan in the study:
         | https://www.bmj.com/content/387/bmj-2024-082194
        
         | JamesBarney wrote:
         | My guess is it's correlational. It's almost always
         | correlational. Remember the knowing a second language reduced
         | risks of dementia, turned out it was correlational. The real
         | cause was under diagnosis in immigrants who were
         | disproportionately more likely to speak a second language.
         | 
         | Still worth investigating further but dollars to donuts it's
         | not causal.
        
       | lupire wrote:
       | The study also shows that taxi drivers have very low lifespan,
       | which of course is highly correlated to ower risk of death by
       | Alzheimer's. They also ignored may other professions with similar
       | or lower Alzheimer's risk.
       | 
       | Overall, it feels suspicious that they ignored other potential
       | explanations for the data.
        
         | apsec112 wrote:
         | They adjust for overall lifespan in the study:
         | https://www.bmj.com/content/387/bmj-2024-082194
        
       | daedrdev wrote:
       | I do wonder though if its cause and effect are the wrong way.
       | 
       | Perhaps the type of person who can remember enough to get the job
       | and be good at it is already less likely to get Alzheimers, and
       | we just selected for those people.
       | 
       | I think this is not very likely though
        
         | apsec112 wrote:
         | Yeah, I don't think the selection into being a taxi driver is
         | that intense though (at least in 99% of markets), it's a fairly
         | low wage job
        
           | iLoveOncall wrote:
           | They should replicate the study in the UK where the test to
           | become a licensed taxi driver is extremely hard and requires
           | years of study to memorize I believe close to 30,000 street
           | names.
        
           | ruined wrote:
           | just because it's low wage and a lot of people know how to do
           | it, doesn't mean it isn't cognitively demanding
           | 
           | and, driving is one of the most lethal activities that people
           | commonly do in the modern world. according to osha 'transport
           | incidents' represent 39% of all occupational fatalities
           | 
           | https://www.bls.gov/charts/census-of-fatal-occupational-
           | inju...
           | 
           | presuming an absence of any survival bias is probably a
           | little cavalier.
        
         | blindriver wrote:
         | I think it's more like those that were taxi drivers that got
         | Alzheimer's quit earlier than those that didn't get it. So it's
         | more like survivor bias.
        
       | mewpmewp2 wrote:
       | I would be really interested in seeing an easily sortable and
       | queriable dataset where you can sort also different causes of
       | death and order them by all professions.
        
       | sys32768 wrote:
       | Did this study identify who had the APOE4 gene?
       | 
       | Another study https://www.nature.com/articles/s41590-023-01627-6
       | suggests the APOE4 gene may be preventing immune cells in the
       | brain from switching to the defensive "clean" mode.
       | 
       | I know my mother's hippocampus was smaller than something like
       | 94% of people her age when she was diagnosed 11 years ago.
       | 
       | First signs of AD generally show up in the hippocampus.
       | 
       | Maybe with heavy spatial reasoning activity in that region, the
       | AD mechanism is stunted or interfered with.
       | 
       | I would be curious to know what activities outside of vehicle
       | navigation stimulate the hippocampus equally. I still play a lot
       | of 3D video games.
        
       | noduerme wrote:
       | A study came out in 2000, back when I was driving a taxi, showing
       | that London cabbies with "the Knowledge" had changes to their
       | brain anatomy.[0]
       | 
       | My girlfriend at the time spotted it in a college course and
       | showed it to me. I remember her joking that she was only with me
       | for the size of my hippocampus.
       | 
       | I would hypothesize that it's more related to spacial/geographic
       | memory than simply navigating spaces one visually perceives. My
       | guess is the effect would be much less pronounced in people who
       | drive for a living now relying on GPS maps.
       | 
       | London taxi drivers, apparently, still must pass the notoriously
       | difficult Knowledge test.[1] A similar (but less rigorous) test
       | was required for Los Angeles cab drivers when I drove. And of
       | course, if you weren't familiar with the street where your next
       | call was (or where your passenger wanted to go), you had only
       | seconds at a red light to leaf through the enormous Thomas Guide
       | and memorize how you would get there.[2]
       | 
       | [0] https://www.pnas.org/doi/full/10.1073/pnas.070039597
       | 
       | [1] https://london-taxi.co.uk/the-knowledge/
       | 
       | [2]
       | https://archive.org/details/losangelescounty0000thom/page/n9...
        
       | DoingIsLearning wrote:
       | Am I interpreting the data correctly in that, whatever protective
       | effect was found on Taxi drivers and Ambulance drivers, was
       | actually aggravated on Ship Captains and Airline Pilots?
       | 
       | My immediate thought went to the negative effect of sleep quality
       | and work schedules, but I would expect the same sleep
       | strain/stress for Ambulance drivers. A lot going on epidemiology
       | wise but interesting study nevertheless.
        
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