Diabetes can be caused by a decreased production of insulin by the body, or a resistance to insulin, reports the New York Times. High blood sugar levels caused by diabetes can manifest in excessive thirst, blurry vision, fatigue, hunger and frequent urination.
Diabetes is caused by insulin resistance or an underproduction of insulin by the body, reports the New York Times. People with type 1 diabetes do not produce enough insulin in their body, while type 2 diabetics have normal levels of insulin but are no longer sensitive to the hormone. Without proper levels of insulin or insulin sensitivity, blood sugar cannot be moved into the body's muscle or fat cells to be used as energy. Thus, individuals with diabetes often have chronic hyperglycemia.
Symptoms of chronic hyperglycemia include excessive thirst, blurred vision, fatigue, hunger, weight loss and frequent urination. If blood sugar levels are over 200mg/dL when tested, medical professionals often recommend diabetes testing. If diabetes remains untreated, serious health problems may result. Eye problems, such as light sensitivity and night blindness, may occur. Infections or sores on the leg or foot can happen, sometimes resulting in amputation. Nerve pain or loss of feeling is common, resulting in erectile dysfunction and digestive issues. Kidney failure can occur, and the chances of heart attack or stroke are higher in diabetics, reports the New York Times.