Can type 1 diabetes be prevented?

No type 1 diabetes can not be prevented.

May 2012
     At present we do not have a way to prevent Type 1 diabetes, but that doesn't mean we aren't trying to find one!  There are many studies around the world looking for the cause of diabetes and ways in which we can prevent it. 
     Australian diabetes researchers are part of the Trial Net Natural History Study, which aims to identify the genes common in families with diabetes.  There are also prevention trials underway as a result of this work. 
     The attached link will take you to the Trial Net website where you can learn more about the work being done to better understand type 1 diabetes and where you can enrol to be a part of the Natural History Study.      http://www.diabetestrialnet.org/index.htm

Type 1 diabetes can't be prevented. Doctors can't even tell who will get it and who won't.
No one knows for sure what causes type 1 diabetes, but scientists think it has something to do with genes. But just getting the genes for diabetes isn't usually enough. In most cases, a child has to be exposed to something else — like a virus — to get type 1 diabetes.
Type 1 diabetes isn't contagious, so kids and teens can't catch it from another person or pass it along to friends or family members. And eating too much sugar doesn't cause type 1 diabetes, either.
While type 1 diabetes can't be prevented, some research suggests that breastfeeding, avoiding early introduction of solid foods, and other factors might play a role in lowering the risk of developing the disease. There's no reliable way to predict who will get type 1 diabetes, but blood tests can detect early signs of it. These tests aren't done routinely, however, because doctors don't have any way to stop a child from developing the disease, even if the tests are positive.
Unlike type 1 diabetes, type 2 diabetes can sometimes be prevented. Excessive weight gain, obesity, and a sedentary lifestyle are all factors that put a person at risk for type 2 diabetes.

Type I diabetes is an example of what is called an auto-immune disease. What that means is that the immune system, which normally gets rid of pathogens like bacteria and viruses, “makes a mistake” and destroys the beta cells in the pancreas (they make insulin) “thinking” that they are pathogens.

As the other contributors have correctly said, both genetic and environmental factors seem to be risk factors. The best known genetic risks entail inheriting particular forms (technically, “alleles”) of what are called MHC proteins. The job of MHC proteins is to help the immune system to get rid of pathogens.

The environmental factors seem to involve viral infections, though which viruses are important is controversial. Essentially (skipping over a lot of technical detail), it seems that a combination of “virus plus particular MHC allele” tricks the immune system into wrongly “thinking” that “beta cell plus particular MHC allele” represents an infection so the beta cells are destroyed. The technical term for this is “molecular mimicry”. 

In short there is no known way to prevent T1D.

There has been small studies with very few patients looking at modifying the immune system to delay the destruction of pancreatic islet cells. These studies showed mixed results.

Possible strategies at improving insulin sensitivity in early T1D that make the endogenous insulin secretion last longer (longer honeymoon). There is also the phenomenon of clinical remission during the first year of T1D (1).

These are beyond the scope of this Q&A.

Regards,
Dr Kevin Lee
BSc(Med), MBBS,MHS(Clin Epi), FRACP
Consultant Physician Endocrinologist

1. Pozzilli P, Manfrini S, Buzzetti R, Lampeter E, Leeuw ID, Iafusco D, et al. Glucose evaluation trial for remission (GETREM) in type 1 diabetes: a European multicentre study. Diabetes Res Clin Pract. 2005 Jun;68(3):258–64.