Long Term Complications: Diabetes

Content provided by the Faculty of the Harvard Medical School

Long-term complications

If it's untreated or treated poorly, diabetes can cause serious complications, such as eye, kidney, and nerve damage. Nearly all complications develop from having high blood glucose levels over many years. These problems threaten people with both type 1 and type 2 diabetes. Vulnerability increases the longer you've had the disease and the higher your blood glucose and HbA1c levels have become.

Experiments on diabetic animals in the 1970s and 1980s showed that tight control of glucose levels reduce complications considerably. However, it wasn't until 1993, when the results of the Diabetes Control and Complications Trial were published, that experts fully recognized the dramatic impact of strict blood sugar control in preventing or delaying complications.

How high blood sugar achieves its nasty ends isn't fully understood, but the answer seems to involve its long-term effects on the body's small blood vessels and on the nervous system. Over time, high glucose levels change the walls of small blood vessels, causing them to thicken and leak. The vessels may eventually clog, impeding blood flow to vital organs.

Last updated:	January 23, 2007