http://www.nof.org/
Part of the website is devoted to the topic of osteoporosis in males.
http://www.nof.org/men/
Canada has its foundation at
http://www.osteoporosis.ca
And Australia is at
http://www.osteoporosis.org.au/
All three websites are chock full of information that every eunuch, and those serious about becoming eunuchs, should read.