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The ones that do stopped being taxi drivers.
Seems strange to me that a specific type of thinking could influence something where most causes being investigated are physical
Taxi driver also live shorter lives than average, which would fit with lower levels of alzheimers. But interesting link nonetheless.
> In one landmark 2000 study, neuroscientists compared the brains of licensed London taxi drivers with those of people who did not drive cabs.

Location is very important here. London cabbies have to pass The Knowledge which is an extremely difficult memory exam that only people with particular kind of brain can do.

My grandfather was a taxi driver and delivery driver for many years. He made it to 93 and I don't recall him dealing with any cognitive decline. He used to tell me different routes to get to a stadium that was closed before I was even born.
Guys... Alzheimer's is 60-80% heritable, and driven largely by APOE genotype. No, you cannot get out of it with One Quick Trick. We have to find therapeutics to make real progress here.

This kind of misdirection is not helpful to the research community, or encouraging politicians to fund effective projects. Everyone WANTS a quick lifestyle change and will latch onto these things, but this is a real biological disease that needs real molecular fixes. Sorry, it's just how it is.

Taxi Drivers: The mean age at death is approximately 67.8 years.

General Population: in the same dataset, life expectancy averaged 74 years.

The average age at which patients are typically diagnosed with Alzheimer's disease is 79.

People in these jobs don't live long enough on average to get diagnosed, at the same rate. The same effect will happen in any job that lowers your life expectancy.

| After adjusting for age, sex, race, ethnicity and education, roughly 1 in 100 taxi and ambulance drivers died of Alzheimer’s, compared with 1 in 60 people overall.

They claim to control for these factors in the 5th paragraph of the article here. Which is a standard thing to do in these kind of studies.

So you're point is either not relevant or that they didn't control for age correctly?

Yepp, they die from circulation related illnesses. Since the sit all day long in the car.
From the article:

    > After adjusting for age, sex, race, ethnicity and education, roughly 1 in 100 taxi and ambulance drivers died of Alzheimer’s, compared with 1 in 60 people overall.
Does that answer your concern?
So many possibilities for error...

Is every case of dementia diagnosed accurately? Is there a difference between professions how likely their dementia is to be diagnosed accurately?

Is there a correlation between dying early and being pre-disposed to have developed Alzheimer if having lived longer? If there is, then the "correction" for age is not correct, because the correction assumes the fraction of the group that died early were equally likely as the rest of the group to develop the disease if they had not died early.

I don't know anything about Alzheimer but it doesn't seem unthinkable that the factors that cause people to die early also could also play a role in causing Alzheimer.

I am pretty sure that a dataset controlling for that would (laughing here) not negate the fact that fewer people who lived past the mean date that are taxi drivers died of a related disorder.

That said, suggesting it is related to the career as opposed to, say, the fact that a higher percentage of taxi drivers carry some other set of genes or genetic markers that either led them in some way to become a taxi driver or contributed to a lack of development of the disorder, is pretty weak. In the United States and I think a few other countries the number of taxi drivers which are immigrants from a handful of countries outnumbers any other type.

And, the world has changed a lot. Are 1980s cab drivers and 1950s cab drivers and 1965 cab drivers and cab drivers from 2007 comparable? are car service and livery drivers?

I find the title highly misleading. The actual claim is a 40% lower chance (1 in 100 as opposed to 1 in 60) for taxi and ambulance drivers when compared to the average. That’s a big drop but the title implies that Alzheimer’s is rare in taxi drivers specifically and I don’t think the difference warrants that claim whatsoever.
First rule of attentioneering - If it bleeds, it ledes

Second rule - Got edge case? Got headline!

Eating eggs actually lowers the risk of Alzheimers.
Something interesting that the original study looked at, but isn't mentioned in the linked article: this effect was not observed for non-Alzheimer's dementia deaths. There seems to be something specific to spatial reasoning and Alzheimer's.
I wonder if the same is also true of other high-spatial-complexity activities like rock climbing and professional dancing? (Exercise level would of course be a counfounding varable to be eliminated in these cases.)
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> London cabbies must memorize more than 25,000 streets within a 6-mile radius of Charing Cross, a challenge known as “The Knowledge” that takes three to four years.

What the hell. I passed all the test for driving cabs in Stockholm, Sweden. I had to memorize 20 regions in the city. I wonder if this requirement applies to all taxi drivers, including Uber.

before or after massive use of navigation apps?
One of the first things to go with Alzheimer's is spacial mapping in the brain so this makes sense. Your exercising daily a part of the brain that is involved.

In addition there's the social component of driving - you may not always want to talk to a Taxi driver but many people do. And ambulance drivers are often socializing with their colleagues

Driving also has a mix of reaction time based skills and hand eye and hand foot coordination. Overall it's pretty complicated.

Writing this I'm realising the final "Turing" test for AI might actually be just replacing the average Taxi driver. Can it drive a car, choose a route dynamically based on day and traffic and weather, and have a conversation with a wide variety of people and topics all at the same time ?

> Risk adjusted percentages and mortality odds ratios were adjusted for age at death, sex, race, ethnic group, and educational attainment using logistic regression.

Adjusting for educational attainment is an intriguing choice. If higher educational attainment were to decrease risk of Alzheimer's disease, wouldn't this adjustment optimise out the factor that they're looking for?

Otherwise very interesting results and conclusions. Also what's up with the outlying occupation on the left side of the 1st 2 charts on page 3: "Personal care and service workers, all other" with a mean age of death of 50.65?

Any studies on chess player and Alzheimer's?
I love HN for articles like these.... hard to find intellectually interesting yet seemingly corner-case statistics like this elsewhere.
I wonder how it will look when we start doing statistics on gamers, if AI doesn't destroy our brains first. Then it would be interesting to plot the different death by genre like for example strategy, FPS, puzzle, etc. Someone else asked about Chess players which is probably also related right.

My grandad essentially died of alzheimers and he just loved to sit and watch football all day where you don't really need to think much.

I wonder if alcohol consumption plays a role here, since it is a known risk factor for Alzheimer’s. A taxi driver who works 60 hours a week will have very little time left over for drinking, whereas pilots have relatively short work hours where they actually need to be sober.
Could it be that the cause/effect relationship here is incorrect? Perhaps only people with the cognitive skills for complex mental maps and spatial reasoning can be effective at driving a cab, so driving a cab may not "protect" you from Alzheimer's at all, but people who have the skills to keep a job as a cab driver have a brain that is less susceptible to Alzheimer's.