In reply to Cara Woodards:
Interesting research - I completed your questionnaire and I was curious as my dad (non-climber) got Dupuytrens in his seventies. Biggest risk factors seem be genetics (Scandinavian/Viking origin) age (usually over 50) and being male.
There was a previous discussion on this about 5 years ago which is worth revisiting if you haven't already:
http://www.ukclimbing.com/articles/page.php?id=1312
Two suggestions for your questionnaire:
1) Your survey focuses on intensity of climbing activity and injuries during the last 12 months, when previous work (see the link above) indicates it is the long-term intensity and injury history over a whole climbing lifetime that are the likely risk factors. You could also (or instead) ask people how many climbs they have done and how long they have been climbing, and their average grade over that whole period. All these stats are potentially available from online logbooks so should be easy for people to give them to you. This should give you a set of indicators or compound index of life-time climbing "intensity" (frequency x difficulty x years' duration). You'd have to keep your questions on training intensity too, as that may be as big a risk factor as climbing intensity, particularly as people train more for each logged climb they do.
2) You ask about height, weight and age, but with genetics such a strong predictor it might be worth asking your survey respondents two additional things: a) whether a parent or close relative has ever had Dupuytrens and b) their ethnicity (in fairly specific terms) - Viking and Celtic seem to be the biggest groups at risk.
When you've taken out the effects of age and genetics, and you have a measure of life-time intensity of climbing, and not just what people are doing this year, you might have a better chance of picking out the link between Dupuytrens and different forms of climbing, or associations with other climbing injuries.
Your consent forms are exemplary and question really clear - nice to see. Good luck with your work!
Eddie