Just heard a little blurb on the morning news about this study. Haven’t been able to find the actual paper but did find an article with more information. This is just a statistical study and does not go into reasons.Interesting fact, Sweden has the second highest number of type 1.
Based on the residential location of all patients at the diagnosis of type 1 diabetes, four significant high-risk clusters were identified, all located centrally in the country (all in the countryside, away from urban centers), where the relative risk of developing T1D was between 30% and 80% higher compared to what would be expected from national averages. No high-risk clusters were observed in people in major cities.
Very interesting indeed, because our ‘clean’ urban environments are sometimes thought to affect our immune systems negatively and contribute to the increasing prevalence of hay fever and other allergies for example. This finding indicates that rural environments also may have some negative effects on the immune system.
I remember reading that our immune systems are designed to protect us from outside invaders such as parasites and bacteria. Between modern medicine and hygiene our immune systems don’t have enough to do, turning against the body they are meant to protect.
The article I read was about having Crohn’s disease drink a glass with a parasite that cannot infect humans. It gave temporary relief from flares. There’s been more research done in tthis area as to whether it is giving the immune system a real enemy or something to do with the gut biome.
There is a hypothesis of why polio became so wide spread in the 20th century. It too blames hygiene and bottle feeding infants. In this hypothesis everyone was infected with the polio virus but received temporary immunity from their mother’s colostrum. The hygiene part is that in the past people weren’t too clean. This is where the children got exposed to the virus, but in a limited fashion. I know I’m not making much sense, but polio was not unknown earlier but it bloomed into an epidemic in the first 50-6- years of the 20th century.
I’m not sold on it. Since we have genes that makes us prone to developing Type 1, most of it originates from Nordic areas with Finland being first and Sweden and Norway following. So it seems to me picking towns with the highest rates in an area that is known that the genes have come from could just be the genetic pool they are getting the stats from, not necessarily the rural town. In small rural towns the genetic pool would be smaller and more prone to being related to each other.
The key thesis is that improved hygiene caused infections to happen at a later age: passive immunity from mother’s milk was no longer there to stop the gut infection from spreading to the nervous system. Infection causes lifetime immunity in any case, but infection during the first few months after mother’s first milk was just “a stomach bug.”
More on the colustrum that CarlosLuis mentioned. It’s a special mother’s first milk loaded with antibodies and nutrients, according to practical knowledge from ovine husbandry. I hear that bovines are similar; I suppose that humans and other mammals also use this mechanism to transfer antibodies from the mother to the newborn. In the last months of pregnancy the ewe’s mammaries collect antibodies and nutrients to form colustrum, and during the first few hours after birth, the lamb gut is “open:” antibodies can pass from the gut to the bloodstream. So whatever antibodies the ewe has from pathogens in the local environment are transferred to the newborn lamb if it drinks the first milk promptly. After about a half day the lamb gut is “closed,” and any supplemental colustrum would just be digested as food without giving passive immunity.