It should be noted that smoking is bad not just for people who have Diabetes but for everyone. Smoking can increase the risk of acquiring various diseases. For diabetics, smoking can narrow their blood vessels which can make it harder for blood to flow to various parts of the body.
By smoking, people can increase the chances that they are going to suffer from heart conditions and problems which can be deadly for people who are already suffering from Diabetes. To help lower the risk, the solution is simple - do not smoke. This is easier said than done though for a lot of smokers.