Ethics approval and consent to participate
The CAP trial was approved by Trent MREC [05/MRE04/78] and the Confidentiality Advisory Group [PIAG 1–05(f)/2006].Trent MREC was a formal research ethics committee of the UK NHS Health Research Authority at the time of submission, but has now been renamed as the "East Midlands—Derby" Research Ethics Committee. All methods were carried out in accordance with relevant guidelines and regulations. The UK Patient Information Advisory Group (now the Confidentiality Advisory Group) gave approval for the identification of men in both arms without consent under section  251 of the National Health Service Act 2006.