DD said to me yesterday that she's quite surprised he hasn't been working publicly with Asthma charities as he's quite big on charity if i remember rightly?
TBH i don't think we should HAVE to know, but i do think it would probably have been very inspirational for children with asthma to know David Beckham did/does
Its the same as my when my son was diagnosed with diabetes, Sir Steve Redgrave was a huge inspiration to him, and even replied personally to the letter he sent him - to a six year old boy dealing with something like that it is really uplifting and motivating!!