Correction: Diabetes Mellitus is not a symptom of erectile dysfunction, however it is a risk factor for development of erectile dysfunction.
Also I don't think these solutions are proven to work.
The causes you mentioned are more of risk factors. The one that's actually a cause is very low testosterone levels. Please do more research, read medical books on topics like this when you're writing them. I like the enthusiasm you have to write about serious health issues in our society though. Cheers