It's unclear how people get the disease — genetics plays a big role, though unknown environmental factors may also trigger the disease. Either way, the disease causes the immune system to mistakenly attack and kill insulin-producing cells, called beta cells, in the pancreas. (This differs from type 2 diabetes, in which the body initially makes sufficient insulin but the cells cannot properly use it.) Without enough insulin working to remove glucose from the blood stream, and allowing glucose to enter the body's cells, blood sugar levels spike. Left untreated, this insulin deficiency leads to a deadly complication called diabetic ketoacidosis. What's more, having high blood sugar over the long term can cause life-threatening complications such as kidney damage or heart disease, according to the Mayo Clinic.
Abnormal cholesterol and triglyceride levels. If you have low levels of high-density lipoprotein (HDL), or "good," cholesterol, your risk of type 2 diabetes is higher. Triglycerides are another type of fat carried in the blood. People with high levels of triglycerides have an increased risk of type 2 diabetes. Your doctor can let you know what your cholesterol and triglyceride levels are.