I was diagnosed with Dupuytren's Contracture a few years ago - well before I had BC. The medicos could not give me a definitive answer as to the cause but the family history of an Irish background (this could be the case as my immediate grandparents were from the UK) and possibly even diabetes were the likely cause.
At the time I was told a local priest, a heavy drinker, had it from his alcohol abuse and his hands were quite crippled. As a result, I massage my hand regularly and try to make sure the fingers don't get bent. 😂
I think there are older posts on Dupuytren's on here somewhere ....