Tinnitus and Diabetes. Tinnitus is a common condition affecting around 50 million adults in the U.S. It's defined as a ringing in the ears that can lead to difficulty concentrating and sleeping. There really is no clear explanation on what causes tinnitus. Many cases can be attributed to prolonged exposure to loud sound or as a side effect of head/ear trauma and hearing loss. A variety of other factors, however, can lead to tinnitus – including diabetes.