Increase in prevalence of Type 1 diabetes: why?

I have not done a study to prove a causal relationship, but I suspect that there would be a correlation between Type 1 diabetics living long enough to reproduce and pass on their genes and the increase of which you speak.

Although I do not discount the environmental factors argument.


That was my first idea too! But I read accounts that mentioned researchers have modeled that and it cannot account for the increase. I did not read the research myself so I have no links.

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I had to check some direct research. I did find an interesting population study that supports your argument. They link the increase to both increase in life longevity (so T1s are present in population longer) and less natural selection pressure:

I would be careful about taking theirs as the last word, though. I am pretty sure quite a few epidemiologists reject their interpretation.

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With better diagnostic capabilities now, adults who previously might have been or were DXed as T2 are now counted in the T1 population. I wonder how much this factor contributes to the increase?


Like the sudden prevalence of Alzheimer’s. Whereas for a good couple thousand years people have simply gone batty or dotty.


There’s been a steady increase in all autoimmune and allergic conditions over the past few decades. Even though all these conditions have different names and have very different symptoms, in a sense they’re all caused by the immune system failing to regulate itself and producing antibodies and other inflammation against a target that is harmless. I don’t think this is a story about Type 1 alone, but rather that the cause of all of these conditions is related, whatever that cause is (environmental factors, surviving longer, better diagnosis).


Anyone interested in reading a book on this topic can pick up “Diabetes Rising” by Dan Hurley. He is a T1 journalist who was aware of the increase in T1 and wrote this book to investigate the topic. He mentions both improved diagnosis, and lower natural selection losses (I like that euphemism for keeping us alive from Michel’s link!), but says that those are not sufficient to explain the extent of the increase. (Also note that in Michel’s link it says “Reduced natural selection may have contributed to the increasing T1D prevalence worldwide.” - not that it explains the whole increase).

He has a chapter each for what he considers the best contenders - 1. population weight gain; 2. babies consuming cow’s milk instead of human milk; 3. persistent organic pollutants in the environment; 4. too little sun and vitamin D; 5. babies not exposed to enough environmental dirt setting up later autoimmune reaction. Personally I found the last one to be the most plausible, though clearly none of them could explain all the cases of T1. And none of them has enough evidence to be clearly the smoking gun (or even the favorite). So maybe it is some combination of these causes, or even some other cause not considered.

So it is an interesting book, but unfortunately it doesn’t answer the question of why. Unfortunately, it seems that we just don’t have that answer yet.


I second @jag1 's book suggestion, it is excellent

I had heard about the book but could not remember the title, thank you!

Here is the link:

Yeah… :slight_smile: