Diabetes, symptoms and treatment
Diabetes mellitus refers to a group of diseases that affect how the body uses blood sugar (glucose). Glucose is an important source of energy for the cells that make up the muscles and tissues. It's also the brain's main source of fuel.
Causes
To understand diabetes, it's important to understand how the body normally uses glucose.
How insulin works Insulin is a hormone that comes from a gland behind and below the stomach (pancreas).
The pancreas releases insulin into the bloodstream. The insulin circulates, letting sugar enter the cells. Insulin lowers the amount of sugar in the bloodstream. As the blood sugar level drops, so does the secretion of insulin from the pancreas. The role of glucose Glucose — a sugar — is a source of energy for the cells that make up muscles and other tissues.
Glucose comes from two major sources: food and the liver. Sugar is absorbed into the bloodstream, where it enters cells with the help of insulin. The liver stores and makes glucose. When glucose levels are low, such as when you haven't eaten in a while, the liver breaks down stored glycogen into glucose. This keeps your glucose level within a typical range. The exact cause of most types of diabetes is unknown. In all cases, sugar builds up in the bloodstream. This is because the pancreas doesn't produce enough insulin. Both type 1 and type 2 diabetes may be caused by a combination of genetic or environmental factors. It is unclear what those factors may be.
Risk factors
Risk factors for diabetes depend on the type of diabetes. Family history may play a part in all types. Environmental factors and geography can add to the risk of type 1 diabetes.
Sometimes family members of people with type 1 diabetes are tested for the presence of diabetes immune system cells (autoantibodies). If you have these autoantibodies, you have an increased risk of developing type 1 diabetes. But not everyone who has these autoantibodies develops diabetes.
Race or ethnicity also may raise your risk of developing type 2 diabetes. Although it's unclear why, certain people — including Black, Hispanic, American Indian and Asian American people — are at higher risk.
Prediabetes, type 2 diabetes and gestational diabetes are more common in people who are overweight or obese.
