That is fairly common with Diabetics ... well, I don't know about being "covered with black" but many really don't take heed and just think the toilet bowl is dirty. It is from excess glucose/sugar in your urine. About 5 years ago I noticed that my toilet was getting these black specs and getting worse and thought it was from a dirty toilet - despite cleaning it often. We have 2 full bathrooms in our home - one for my wife and one for me
I noticed that her's did not get these black marks but mine did. I mentioned it to my doctor and he told me what it was from. That is when he started testing for glucose. Drinking that "syrup" for a glucose tolerance curve was not pleasant, but that and subsequent tests showed elevated readings and a comment about being pre-diabetic.
To elaborate further for "Listlad" and the original post for research, I was 65 at the time and really cannot think of any other stand-out warning signs before that, except for .....
Diabetes is an inherited genetic gift from my mother's side of the family, traced back a few generations. She is now 93 and has been a T2 on insulin for about 15 years. Earlier generations, my Mom's father, grandfather, and great grandfather, died at a young age (50s) from Diabetes. Diabetes recognition and treatment were not the same many years ago and longevity was not common for Diabetics. So, for me, a closer look at my maternal family tree would have been a warning of things to come. I have a younger sister also with T2, and another sister pre-diabetic. 2 brothers and a 3rd sister (all younger than myself) seem to be OK, so far. We have 2 daughters and a son, in their 40s, and 3 grandsons. Hopefully, the family curse has no been passed to them.
Did my younger years with a "sweet tooth" exacerbate the final outcome of landing up with T2? I was never overweight except for a just over a year before T2 diagnosis when I had an urge to eat a lot and shot up to 205 lbs (14.6 stone) but 6 feet tall - before I was always tall, slim, and light-weight. Now steady around 160 lbs (11.4 stone) thanks to a better diet and oral meds (Jardiance).
So while I obviously had the propensity for Diabetes, it never stood out like a sore thumb. Maybe my doctors, over the years, really didn't think that showing a little high (in the "normal" range) was anything to be concerned about.
My HbA1c is now 6.3, so a downward trend after diagnosis and taking better care of myself through diet.
Hope that helps in your research "Listlad" and an explanation for "milesrf" about your post reply/question.
We may all have T2 Diabetes but our body's combination lock can be complex.