Dupuytren's disease is more common in diabetics. It is linked to Viking ancestry and so is more common in western Britain and the South/ Channel Islands (Normans). In the feet it is called Lederhosen disease. If it causes restriction of finger extension then it can be operated upon. Surgeons try to avoid operating on the feet for this disease as much as possible (mainly for painful lumps).
It is thought to be related to abnormality of triglyceride metabolism and is also seen more commonly in epileptics, alcoholics and diabetics. It can be very slowly progressive, but in some unfortunates it can be more aggressive and need repeat surgery (more commonly seen in people who start younger, have a strong family history, have Lederhosen disease, have thick knuckle 'Garrods' pads, and a Peyronie's disease [look it up]).
If you can put your hand flat on a surface, there is no need to worry (Hueston's table top test).