There's certainly an increased risk of ill effects, but the evidence is overwhelming that if one can keep reasonable control the chances are greatly reduced.
My son has type 1 and it is very difficult, if not impossible to maintain HC1A levels which a normal person would have. Maintaining proper blood sugar is vital is reducing the possible ill affects of diabetes, but I think most doctors would say you can reduce the chances in type 1 diabetics, but never to the level of a non diabetic.