[1] Queen Mary Univ London, Ctr Sports & Exercise Med, Barts & London Sch Med & Dent, Mile End Hosp, London E1 4DG, England
[2] Univ Rome Foro Italico, Dept Hlth, Rome, Italy
[3] Univ Roma La Sapienza, Dept Phys Med & Rehabil, Rome, Italy
[4] London Sch Econ, Dept Social Policy, London WC2A 2AE, England