Geographic variation in T1 incidence: why?

I think there must be a lot of factors at play in the higher incidences: genes (HLA complex prevalence), ethnicity makeup of the countries (Caucasians are more at risk for developing T1D), their national healthcare system (we know infections may be that 2nd hit necessary, so country’s initiatives for vaccines or infection prevention measures may play a role), probably something to do with geography or climate or diet could be playing a role???

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Additionally, there are at least ancedotal reports of spikes such as this one:

https://www.clarionledger.com/story/news/local/2017/09/16/diabetes-spikes-among-mississippi-children-and-no-one-knows-why/665235001/

Which lends some credence to the genetic predisposition, followed by a viral or other environmental trigger.

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yep! I know anecdata is just anecdata and we can never really figure out for sure. But I can’t help noticing that the same year that Samson was diagnosed, there were a ton of “welcome new family” messages in our local diabetes support group where the kids were roughly the same age as Samson. As if a particular bug was going around that tended to hit kids of the same age, and some of them wound up getting T1D

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My guess is that there are definitely common gene factors that put one at risk for these things, but then also probably many different factors that can trigger them, which is why they are probably so hard to pin down. Especially when you add to it the fact that it may also be a roll of the dice as to whether the person exposed to that trigger goes on to develop Type 1, celiac, or any other autoimmune condition. Also, I’ve read in books that whether the immune system generates antibodies or not may depend on the state of the rest of the body at the time of exposure to something else…so that may be yet another factor that compounds things.

Different condition (though also autoimmune), but when I developed Graves’ disease, there was a lady working in my office who also had long-term Type 1. She was diagnosed with Graves’ disease literally within about a month of me. So we joked that it was something in the water at the office that triggered it. And who the heck knows, maybe it was!

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I thought that was thought to be related to less sunshine, and lower vitamin D levels.

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Welcome to the forum Kalle. Your comment about Sweden having the second highest rate of T1D in the world interested me. Do you have more information on which other countries have high rates of T1D?

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I found this ytube very interesting and have posted about it before (not exactly sure when/where though).

At the 38:11 mark it shows a graphic of how, in Finland, the recommended dose of vitamin d dropped and the increase of type 1 diabetes increased.

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I notice he says Rochester NY, instead of Rochester MN (on chart).
Rochester NY is very cloudy, not sure about MN.

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My clinic is participating in a long-term study called TEDDY which is trying to identify the causes of T1D by following a large number of participating children over many years. My university has a page where they publish results, but it’s in Swedish. Some of the participating universities are in the US though, so I would think that there’s information available in English somewhere.

They have confirmed a correlation between low levels of vitamin D and autoantibodies, and have also found a number of connections to various genes, in addition to the ones previously known. Still, it seems difficult to draw firm conclusions because the incidence, in absolute numbers, is still small. Even with thousands of participants in 4 countries, only a little more than 300 have actually developed Diabetes. One of the upsides is that it can be detected long before it causes any symptoms at all. This means no DKA, and a slower destruction of Beta-cells with early administration of insulin. There has been some discussion about general screening of all newborn children for this reason.

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When Liam got diabetes, he was still breast feeding.

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I’m sad to hear that he got it so early. That makes it seem very random and unfair, which I suppose isn’t far from the truth. Even though some genetic markers increase the risk significantly, in most cases there is no observable heredity at all. I guess all that randomness can obscure the patterns.

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Forgot to add that no one on either my wife’s or my side had ever had T1D before either.

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Same for us, no T1D in the family. I suspect when all is said and done, some variants will have strong hereditary influence (i.e. families with multiple T1D children and parents) and others will be more influenced by some genetic mutation that occurs and will eventually be identified. Either way, the suck is real.

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there’s a correlation with low vitamin D levels but i’m not sure if that means giving a vitamin D supplement will then end up preventing it. I can’t remember but I think they’ve done some studies to that effect, with discouraging results.

We have no T1D in our family, but my husband’s dad and grandma had Hashimoto’s thyroiditis. My grandmother had MS and my dad’s siblings had rheumatoid arthritis and what we think may be lupus. So autoimmunity does seem to run in the family.

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Totally agree—this is an unwarranted logical jump. Not only do we have no idea if a vitamin D supplement can actually provide vitamin D to your system, but it could well be that the low vitamin D correlation is a consequence of something that causes both.

Also right, at least for their consequence on osteoporosis:

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We have no T1D in my family, besides me (and no T2 whatsoever). I have a first cousin with Graves’ disease, but that’s the only known major autoimmune disorder in my extended family. I would imagine that there are multiple risk pathways, some involving heavier genetic components (such as in families with major patterns of T1/celiac/thyroid disease) and others with weaker genetic factors. I would not rule out pathogenic factors (e.g., viral, bacterial, etc) as key components in triggering the autoimmune reactions, especially for those of us without major hereditary patterns.

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Early in my scientific career I had the opportunity to have a class with a really smart young scientist who specialized in absorption of vitamins. Most of her work at the time centered around how nature packages vitamins, how much was absorbed from a dose, and what co-factors are required for or that accelerate absorption. Now I am no expert, but from what I gathered, taking a pill that contains little to none of the co-factors required for absorption and expecting absorption to occur isn’t a great way to spend my money.

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I’ve always been a bit confused about vitamins and supplements. I’m not one to spend my money on them, either. But a few years ago my vitamin D level was tested and came back at 19 (converted to US numbers), so my GP told me to take vitamin D supplements. When I told my endocrinologist, he said I should just continue taking them indefinitely. I had my level re-checked last year and after years of supplements it was 36, which some seem to consider normal and some seem to consider low. I’ve continued taking vitamin D supplements, since I figure they can’t hurt. I’ve added vitamin B12 and iron supplements in the past few months because those levels are also low and my doctor (specifically GP and cardiologist) advised me to.

As for family history, I’m the only person with Type 1 diabetes (or any diabetes) anywhere in my immediate or extended family. However, various members of my extended family have had Hashimoto’s, Graves’ disease, rheumatoid arthritis, Crohn’s disease, and probably others I’m not aware of. So there’s definitely a history of autoimmunity there, as well as a strong history of various allergies. In my case, I figure the fact that I was born very premature and spent the first four or five months of my life in the hospital screwed up the “learning” and “fine-tuning” of my immune system. I feel that this, combined with my genetic predisposition, is why my immune system has always been a bit out of whack and I’ve had autoimmune and allergic problems basically my entire life.

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I will interested to know if your levels of the other supplements comes into range. On the vitamin D front it would be interesting to see what happened to your levels if you increased your sunlight exposure a bit and added a meal with wild caught salmon once a week.

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both Samson and my younger son have low vitamin D levels but I sort of wonder too if the gummies they take make a big difference or if the real solution is to just get them out in the sunshine. This article I found interesting:

That said, there’s not much you can do during the winter when it’s pouring rain (atmospheric river here!) and they have to be inside a school building for most of the good hours of sunshine.

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