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Comment by ablyveiled | Hacker News Reader

This would not explain the precipitous rise in Alzhemier's rates seen in developed countries and mostly in the last few decades. I maintain that alzheimer's is type 3 diabetes.

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There's a precipitous rise in old people, and especially otherwise healthy old people in developed countries. All those who would have died of perhaps an upper respiratory disease or an untreated infection before they had a chance to develop Alzheimer's are no longer being eliminated early. We see similar trends for most age related diseases like cancer and heart disease. It's only natural that as we get better at dealing with diseases we can cure we would see more of the ones we can't. That's not to say there couldn't be other environmental factors at play, but a rise in Alzheimer's does not necessarily mean a rise in whatever causes Alzheimer's.

> All those who would have died of perhaps an upper respiratory disease or an untreated infection before they had a chance to develop Alzheimer's are no longer being eliminated early.

OP claimed a rise in rates, not absolute numbers. Is there any plausible reason that reducing other causes of mortality might possibly cause a rise in fraction of the elderly population that develops Alzheimer's?

Depends if they meant rates or rates by age. If you mean population rates, then rising life expectancy caused by a decrease in other causes of death would absolutely increased overall pop alzheimer's rates.

If other causes of death were eliminated, you might also see an increase in alzheimer's amongst those in the same age bracket. This might be clearest with an example.

Suppose we eliminated heart disease. Life expectancy would increase. What would happen to the rates of other disease? They would go up within age groups. Because you still have to die of something. If heart disease can't take someone out, that means some other factor will be available. Much of the time people have more than one condition.

And this effect produces an increase in rates. Let's say that an entire population gets two dice. They roll the first one, if it's even they're out, otherwise they roll the next one. About 1 in 12 people are going to roll a 6 on that second dice. Now let's say for that first dice, you're only out if you get a 6. Now the odds of getting a 6 on the second dice is about 1 in 7, not because the second dice is any more likely to get a 6 but because a greater percentage of people who would roll 6's are rolling that second dice. The first dice in this analogy are diseases that we can now deal with, the second dice are the more intractable diseases.

Depends on if the rise is specifically in the fraction of the elderly population, or if it's in the fraction of the general population.

If the rise is in the fraction of the general population, then an increase in the proportion of the general population that was elderly would be expected to increase the numbers of a disease of the elderly, even if nothing was happening.

If there were a rise in the proportion of e.g. 80 year-olds that were developing Alzheimer's, that'd be a different story. Although you'd still have to ask yourself if some of the conditions that were increasing the proportion of the population that are 80 year-olds were disproportionately extending the life of people with a propensity for Alzheimer's.

It doesn't have to be mutually exclusive. Metabolic syndrome causes all sorts of general havoc with just about everything you can think of, which would probably include neuron's ability to maintain homeostasis or fight a latent infection.

Most everyone (at least older people who never got a chickenpox vax) has a latent varicella zoster (the shingles/chickenpox virus) infection, but only a minority will get Alzheimer's. It could easily be true that varicella is causal in most Alzheimer's, but also that many of those cases would never have happened without compounding risk factors like metabolic syndrome.

We’ve had rises in herpes viruses in developed countries. Shingles is a type of herpes virus. So I wouldn’t be too quick to make that judgment. Also in an aging population, it would have to be a relative rise in Alzheimer’s, not an absolute one. I don’t know the data, so I can’t say which it is.

But Alzheimer’s is a complex disease, it may well be there are multiple factors involved. I also am inclined to think there’s something to your hypothesis, there is some data to support it.

I almost brushed off your message at first, but decided to look it up. You have now made me aware of something I had never heard of, thanks!

https://www.verywellhealth.com/why-is-alzheimers-called-type...

It’s a bunch of crap. Maybe shouldn’t look for medical information from a social worker on a clickbait site.

Diabetes (specifically Type 2) is correlated with Alzheimer’s - how that makes for a useful new classification of diabetes is nonsense.

This would be about as sensical as calling nicotine addiction Type 2 lung cancer.

It also doesn’t help

> However, classifying Alzheimer's as type 3 diabetes is controversial

No, not in the medical community it isn’t. That there are some crackpots and quacks out there doesn’t change that - there is not serious debate ongoing about this in medicine.

It wouldn’t be a viable name anyway as the number 3 has already been reserved/in common use in actual clinical and research practice for pancreatogenic diabetes.

>> precipitous rise in Alzheimer's rates in developed countries

Besides the older human demographics, it's certainly possible the virus strains are evolving to be more aggressive and cause problem more often. From a virus perspective, it wants to be as viral as possible without killing the host. Alzheimer's seems like a reasonable allowance.

It might explain it if herpes is implicated..

> I maintain that alzheimer's is type 3 diabetes.

With type 1 diabetes there is growing evidence that coxsackievirus B virus is somehow involved.

Better diagnoses, more funding for diagnosis, more general knowledge of x, more sensitive tests for Alzheimer's. Those are the most likely culprits whenever you see a "oh no, rates are going up" headline. True for autism. True for this.

You don't believe that our foreign environment has something to do with it?

AFAIK the rise in Alzheimer's was well correlated with the rise in life expectancy.

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