Only a small percentage of the population suffers from Dupuytren's disease. Therefore most people taking glucosamine etc. will not have any problems with DC. However, it's a fools gamble to take the stuff if you're one of the afflicted.

I'd been taking glucosamine for years - probably starting in my early 40s. At age 50 the first nodules appeared and I stopped taking glucosamine since it is a collagen growth stimulator. After a few years with the nodules and no contraction I decided to retry glucosamine/chrondroitin supplements. Within days the nodules, which were dormant, began throbbing and slightly painful. Within days after ceasing the supplements, the nodules again became dormant.

Granted this is not a double blind study, but should be sufficient warning to those wise enough that if you have dupuytren, taking glucosamine/chrondroitin supplements is dangerous, potentially foolish, and may accelerate this disease.