25. Could I have had diabetes for a long time and not known it?
Yes, indeed, you could have had diabetes for a considerable period of time, months or even years, and been unaware of it. However, it is unlikely that you could have had severe diabetes with very high blood sugars for a long time without having to seek medical attention, as you would have experienced complications.
However, milder degrees of diabetes are often without obvious symptoms, although in retrospect patients will realize that all was not well when they start to feel the benefits of treatment. Studies have shown that, on average, type 2 diabetes has been present for several years by the time it is diagnosed.