1. The MRC Lifecourse Epidemiology Unit (University of Southampton), Southampton General Hospital, Southampton, SO16 6YD, UK
2. National Institute of Health Research (NIHR) Musculoskeletal Biomedical Research Unit, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Nuffield Orthopaedic Centre, University of Oxford, Windmill Road, Oxford, OX3 7LD, UK
3. Victoria University of Wellington, Wellington 6140, New Zealand