Comment by vitorfblima
1 year ago
From the paper: For example, the Centres for Disease Control generated an independent estimate of average longevity across the USA: they found that Loma Linda, a Blue Zone supposedly characterised by a ‘remarkable’ average lifespan 10 years above the national average, instead has an unremarkable average lifespan29 (27th-75th percentile; Fig S6).
This misses the forest for the trees.
The CDC looked at average life expectancy in Loma Linda across all demographics. Purely geographical and on average.
The blue zones focused on the greater longevity specifically of Adventists in Loma Linda.
It wasn't a question of whether living inside the municipal boundaries of Loma Linda automatically conferred some special health benefits -- clearly it doesn't.
It was, "Why is there an unusually high concentration of outliers living here, and what behaviors cause them to live longer than average?"
There are ~9000 Adventists in Loma Linda. This is two categories you can split people into, then intersect.
There are 330,000,000 million Americans. There are likely millions of categories people can be split into. Just for fun let's say counties (6000+) then any of a zillion other cross items (left handed, blue eyed, above average height, smells like butter, etc., etc.,Etc.) Say we find 10,000 of these categories.
Life expectancy is decently modeled as a gaussian with std deviation 8 years. A 10 year excess is a z-score of 1.25, and 10% of samples will be at this point.
The odds of TONS of subsets of size 9000 of the 330,000,000 people that can be found in the same pair of county+trait from the 600,000,000 pairs is nearly 1.
Thus the Adventists in Loma Linda are far more likely to be one of these many blips that have zero causal power than they are to have special life sauce. Finding them is merely an artifact of being able to filter data, not a special power of the objects.
Or a simpler way: pick two binary traits, split the 330m Americans into 33,000 chunks of size 10,000 where each group has all in one of the four pairs of traits, and you would expect (more or less - there is some more math to do here) that 10% of these groups has average lifespans over 10 years, i.e., 3,300 of the groups are the same as the Loma Linda Adventists.
No magic needed. Just rolling dice.
If "no magic is needed", then why don't you - or someone else - name, say, 5 more such groups/chunks with their exact characteristics? It seems that it is not that easy to find them... and yet someone found such a group in Loma Linda...
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I don't think that is right. In the Blue Zones marketing material, they characterise Loma Linda's 9000 Adventists, who make up 40% of the population, as living a decade longer on average. That is the claim being investigated. This claim is hard to reconcile with the CDC's official numbers which show a typical life expectancy for the entire area, unless living next to Adventists somehow lowers the life expectancy for the remaining 60% of the population, which would be far more interesting.
> they characterise Loma Linda's 9000 Adventists, who make up 40% of the population, as living a decade longer on average
> This claim is hard to reconcile with the CDC's official numbers which show a typical life expectancy for the entire area
Buettner's focus was on the outliers. Loma Linda is a longevity hotspot, and the question is why.
He found the long-living outliers practiced certain behaviors that they associated with Adventism, like vegetarianism.
Not all Adventists practice those behaviors. About half of Adventists eat meat, for example.
But the long-living outliers were Adventist and practiced the behaviors that he highlighted. So that was his takeaway.
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> It was, "Why is there an unusually high concentration of outliers living here, and what behaviors cause them to live longer than average?"
Blue Zones LLC also provided a set of answers to that question, and one of those answers (“drinking 1-2 glasses of wine per day”) is clearly not true in this case.
And honestly, it’s just Bayesian statistics—if they present 5 data points, and 4 of those data points are floating somewhere between data errors and fraud, then odds are, that last data point is flawed somehow as well. Certainly they would need to do some extra work to prove that it isn’t.
So first it was Sardinia, Okinawa, Ikaria, Loma Linda. Then it's not even Loma Linda but specifically Loma Linda Adventists. That looks like XKCD-level p-hacking
https://www.xkcd.com/882/
Yeah, if the point is really about Adventists, I think it's better made with statistics on them. Ditto teetotalers or vegetarians (Adventists are often both). Or if it's about studying individuals with long lifespans, then great, let's do that.
I don't get your point.
Who's claiming that living inside the boundaries of such zones would confer health benefits?
The paper is pointing out that if you actually look at the data there is nothing remarkable about the region's average lifespan (actually lower than the entire country of Japan), which is what's being discussed here.
> The paper is pointing out that if you actually look at the data there is nothing remarkable about the region's average lifespan
That's my point -- the region's average lifespan is irrelevant. It's only relevant given the misconception that Loma Linda itself has some special properties of rejuvenation.
But that doesn't mean it's not a longevity hotspot. Even if the average lifespan there were lower than normal -- say a large number of unhealthy people lived there -- it still wouldn't negate that, if an abnormally high number of healthy centenarians also live there.
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> This misses the forest for the trees.
In a large enough forest, there's always one or two randomly weird trees.
yeah but there isn't a cluster of 100 trees, all sharing the same religion. they are a cluster, the Adventists, that is.
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> It was, "Why is there an unusually high concentration of outliers living here, and what behaviors cause them to live longer than average?"
Isn't there bound to be some random noise?