1 MRC Epidemiology Unit, School of Clinical Medicine, Institute of Metabolic Science, University of Cambridge, Cambridge Biomedical Campus, Box 285, Cambridge, CB2 0QQ, UK.
2 Yonsei University, Seoul, Republic of Korea.
3 University of Copenhagen, Copenhagen, Denmark.
4 Department Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway.
5 MRC Epidemiology Unit, School of Clinical Medicine, Institute of Metabolic Science, University of Cambridge, Cambridge Biomedical Campus, Box 285, Cambridge, CB2 0QQ, UK. soren.brage@mrc-epid.cam.ac.uk.