[1] Univ Manchester, Manchester Royal Infirm, Dept Med & Endocrinol, Androl Res Unit, Manchester M13 9WL, Lancs, England
[2] Univ Manchester, Hlth Methodol Res Grp, Manchester M13 9WL, Lancs, England
[3] Univ Manchester, Ctr Rehabil Sci, Manchester M13 9WL, Lancs, England
[4] Univ Auckland, Freemasons Dept Geriatr Med, Auckland 1142, New Zealand