In 2009, the 10 leading causes of death in the US were, in rank
Heart disease: 599,413
Chronic lower respiratory diseases: 137,353
Stroke (cerebrovascular diseases): 128,842
Accidents (unintentional injuries): 118,021
Alzheimer's disease: 79,003
Influenza and Pneumonia: 53,692
Nephritis, nephrotic syndrome, and nephrosis: 48,935
Intentional self-harm (suicide):
So Diabetes ranked number 7 that year.
I recently saw an old article online that said diabetes was the third leading cause of death in the US, after heart disease and cancer. I don't know what year that was, but since it is the seventh leading cause now, we have certainly come a long way.
The link below says that the life expectancy of type 1 diabetics is almost as good as that of non diabetics: