It is also called type I diabetes. You did not catch diabetes from someone else. Instead, insulin-dependent diabetes is caused by damage to the pancreas. The pancreas is an organ near your stomach. The pancreas contains cells called beta cells.
Beta cells have a vital job.
They make insulin, a hormone that helps cells take in the glucose they need. Sometimes, the beta cells get wiped out and cannot produce insulin anymore. Without insulin, glucose stays in the blood instead of going into cells. Many things might have killed your beta cells. But in most people with insulin-dependent diabetes, the immune system makes a mistake.