Causes

The exact cause of prediabetes is unknown. But family history and genetics appear to play an important role. A lack of regular physical activity and being overweight with excess fat around your abdomen also seem to be important factors.

What is clear is that people with prediabetes don't process sugar (glucose) properly anymore. As a result, sugar builds up in the blood instead of doing its normal job of giving energy to the cells that make up muscles and other tissues.

Most of the glucose in your body comes from the food you eat. When food is digested, sugar enters your bloodstream. Moving sugar from your bloodstream to your body's cells requires a hormone called insulin.

Insulin comes from a gland located behind the stomach called the pancreas. Your pancreas sends insulin to your blood when you eat.

As insulin circulates, it allows sugar to enter your cells — and lowers the amount of sugar in your blood. When your blood sugar level starts to drop, the pancreas slows down the secretion of insulin into the blood.

When you have prediabetes, this process doesn't work as well. Your pancreas may not make enough insulin or cells become resistant to insulin and don't allow as much sugar in. So, instead of fueling your cells, sugar builds up in your bloodstream.