What causes type 1 diabetes?
There’s been a global rise in type 1 diabetes for the past decades, and we don’t know why. The increase is exponential at 3% per year worldwide. On a country-to-country basis, the incidence is higher in northern Europe and Canada than in South America and Asia. We find the highest rates in Finland followed by Sardinia, but we also see high numbers in the Scandinavian countries and the UK.
We used to call type 1 diabetes early-onset diabetes, and we considered it a disease of childhood. However, we now estimate that fifty percent of type one diabetics get diagnosed as adults, so it’s far from it. While there’s a strong correlation between the rise in type 2 diabetes and the obesity epidemic, this is unlikely to link to type 1 diabetes. Finding the cause would go a long way in trying to stop the rising incidence of the disease. For some reason, there’s an autoimmune attack on the insulin-producing beta-cells of the pancreas. While we don’t have a leading theory, there’s a lot of speculation into how it happens.
Seasonality is a factor in the diagnosis of type 1 diabetes. There’s a significant increase in incidence during the autumn and winter season. Nations further away from the equator are more likely to exhibit this seasonal variety, which implicates climate as a potential factor.
Low exposure to sunlight during the winter months reduces vitamin D levels. In turn, this decreases the inhibitory effect of vitamin D on T-lymphocytes. The immune system is also more stimulated by viral infections during the winter months. Both these things could lead to a higher autoimmune activity which is the cause of beta-cell destruction. One leading theory is that a virus triggers type 1 diabetes, such as the common cold or flu. Since it often manifests in the weeks following a viral infection, it’s a credible suspect.
Scientists have identified certain high-risk genotypes for type 1 diabetes. Most likely though, is that a combination of genetic susceptibility and environmental factors cause the disease. The higher incidence rate adds to the already stretched health care system in most countries. More research into what causes type 1 diabetes is clearly needed. If we could figure out the cause, we could identify people at high risk, with the possibility to prevent the onset of type 1 diabetes. We also need to continue investigating promising treatment approaches like immunotherapy and beta-cell or full islets of Langerhans transplantations.