[1] Kings Coll London, Sch Life Course & Populat Sci, Addison House,Guys Campus, London SE1 1UL, England
[2] Univ Southampton, Fac Environm & Life Sci, Highfield Campus, Southampton SO17 1BJ, England
[3] Keele Univ, Ctr Musculoskeletal Hlth Res, Sch Med, Keele ST5 5BG, Staffs, England
[4] Brighton & Sussex Med Sch, Dept Primary Care & Publ Hlth, Falmer BN1 9PS, England