A large US Donor Study record has just been processed on March 21, 2013
http://clinicaltrials.gov/ct2/show/NCT01158742This is extremely exciting as the study has been sponsored by several US government organizations and the Principal Investigator is with the Mayo Clinic.
The study results have not been posted yet but you can see the criteria & bookmark this page to check for future Study Results.
There is even a link which explains How to Read A Study Record.