alt Hacker NewsAlzheimer's disease mortality among taxi and ambulance drivers (2024)
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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-...
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...
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.
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.
>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"
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'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).
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 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
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.
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).
I wonder if the benefit is conferred by navigating around open world videogames for n hours per day.
So why not bus drivers? Supposedly because their routes are fixed?
>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.
Let's hope flying cross country using pilotage has a similar benefit, if one truly exists.
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.
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 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 assume that was a generation that didn’t use Google Maps.
I cannot navigate for to save my life, if this ends up be causal i'm so screwed
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?
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.
Would be interesting to see whether spatial reasoning from gaming shows the same association.
Interesting cause that oxidative stress is particularly lower for them.
What about other driving occupations?
- fire, police, postal, long haul trucks
That's interesting, all of that Spatial Processing and critical thinking keeps the brain juicy.
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?
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”
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Hey! Its time to make some crazy money! Are you ready? Here we go!
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.