Diabetes is not contagious. Its cause is unknown, but genetics, obesity, and environmental factors such as viruses are believed to have roles. Although there is no cure, diabetes can be controlled. The pancreas makes little or no insulin. This type used to be called juvenile diabetes because it often occurs before age 20.
Symptoms begin suddenly, within days and weeks.
The most common ones include frequent urination, excessive thirst, extreme hunger, sudden weight loss, fatigue, irritability, nausea, vomiting, blurred vision, poor healing of cuts, frequent infections, drowsiness, and tingling or numbness in the hands or feet. Treatment includes daily insulin injections, diet, exercise, and self-testing of blood glucose. The pancreas makes an insufficient amount of insulin, and the body fails to use it correctly. This is the most common type of diabetes. It used to be called adult-onset diabetes because it often occurs in people who are overweight and over 30 years old.