| I think mostly it is genetics for Type 1s. I am at least the 8th person in my family to have it and be on insulin. It could be caused by viruses, who knows. I had two colds within two months of each other the fall before I was diagnosed and I hated my job I was at so there was that stress and not getting enough sleep and stuff. I had chickenpox as a kid, and bronchitis (I think) and many colds and flus growing up.
For T2s, I don't doubt that obesity and all the unnatural things in our environment contribute to it. I think medications causing it is a bit far fetched, but many of these drugs have not been around long enough for us to really know all the long term effects of them. | 
