[1] Univ Bristol, Bristol Med Sch, Populat Hlth Sci, Canynge Hall, Bristol BS8 2PL, England
[2] Newcastle Univ, Fac Med Sci, Newcastle Upon Tyne, England
[3] Univ Cambridge, MRC Epidemiol Unit, Cambridge, England
[4] Univ Sheffield, Hlth Sci Sch, Sheffield, England
[5] Univ Bristol, Ctr Exercise Nutr & Hlth Sci, Sch Policy Studies, Bristol, England