There are several risk factors that may make it more likely that you’ll develop type 1 diabetes—if you have the genetic marker that makes you susceptible to diabetes. That genetic marker is located on chromosome 6, and it’s an HLA (human leukocyte antigen) complex. Several HLA complexes have been connected to type 1 diabetes, and if you have one or more of those, you may develop type 1. (However, having the necessary HLA complex is not a guarantee that you will develop diabetes; in fact, less than 10% of people with the “right” complex(es) actually develop type 1.)
Other risk factors for type 1 diabetes include:
Viral infections: Researchers have found that certain viruses may trigger the development of type 1 diabetes by causing the immune system to turn against the body—instead of helping it fight infection and sickness. Viruses that are believed to trigger type 1 include: German measles, coxsackie, and mumps.
Race/ethnicity: Certain ethnicities have a higher rate of type 1 diabetes. In the United States, Caucasians seem to be more susceptible to type 1 than African-Americans and Hispanic-Americans. Chinese people have a lower risk of developing type 1, as do people in South America.
Geography: It seems that people who live in northern climates are at a higher risk for developing type 1 diabetes. It’s been suggested that people who live in northern countries are indoors more (especially in the winter), and that means that they’re in closer proximity to each other—potentially leading to more viral infections.
Conversely, people who live in southern climates—such as South America—are less likely to develop type 1. And along the same lines, researchers have noticed that more cases are diagnosed in the winter in northern countries; the diagnosis rate goes down in the summer.
Family history: Since type 1 diabetes involves an inherited susceptibility to developing the disease, if a family member has (or had) type 1, you are at a higher risk.
If both parents have (or had) type 1, the likelihood of their child developing type 1 is higher than if just one parent has (or had) diabetes. Researchers have noticed that if the father has type 1, the risk of a child developing it as well is slightly higher than if the mother or sibling has type 1 diabetes.
Early diet: Researchers have suggested a slightly higher rate of type 1 diabetes in children who were given cow’s milk at a very young age.
Other autoimmune conditions: As explained above, type 1 diabetes is an autoimmune condition because it causes the body’s immune system to turn against itself. There are other autoimmune conditions that may share a similar HLA complex, and therefore, having one of those disorders may make you more likely to develop type 1.
Other autoimmune conditions that may increase your risk for type 1 include: Graves' disease, multiple sclerosis, and pernicious anemia.