1. a King's College London, Wolfson Centre for Age-Related Diseases, Guy's Campus , London, UK
2. b Department of Psychiatry , Stavanger University Hospital , Stavanger, Norway
3. c School of Medicine , University of Bergen , Bergen, Norway
4. d Psychological Medicine , Institute of Psychiatry, King's College London , De Crispigny Park, London, UK
5. e Department of Sports Medicine , Norwegian School of Sport Sciences , Oslo, Norway
6. f K Richardson, S Day, S Gupta, H Keage, S R Kondapally Seshasai, D Llewellyn, W Muangpaisan F McDougall, G Savva, S I Sharp, BC Stephan