[1] Univ Hosp Trust, Southampton, Hants, England
[2] Univ Southampton, MRC, Lifecourse Epideiniol Unit, Southampton SO9 5NH, Hants, England
[3] Univ Oxford, NIHR Musculoskeletal Biomed Res Unit, Nuffield Dept Orthopaed Rheumatol & Musculoskelet, Oxford OX1 2JD, England
[4] Victoria Univ, Wellington, New Zealand