Complications
A key goal of diabetes treatment is to prevent complications because, over time, diabetes can damage the heart, blood vessels, eyes, kidneys, and nerves, although the person may not know damage is taking place. It's important to diagnose and treat diabetes early, because it can cause damage even before it makes someone feel ill. How diabetes causes long-term problems is unclear. However, changes in the small blood vessels and nerves are common. These changes may be the first step toward many problems that diabetes causes. Scientists can't predict who among people with diabetes will develop complications, but complications are most likely to occur in someone who has had diabetes for many years. However, because a person can have diabetes without knowing it, a complication may be the first sign.