[1] Univ Southern Denmark, Dept Sports Sci & Clin Biomech, Ctr Res Childhood Hlth, Res Unit Exercise Epidemiol, DK-5230 Odense, Denmark
[2] Bispebjerg & Frederiksberg Hosp, Ctr Clin Res & Prevent, DK-2000 Frederiksberg, The Capital Reg, Denmark
[3] Univ Copenhagen, Dept Publ Hlth, Sect Environm Hlth, Oster Farimagsgade 5, DK-1014 Copenhagen, Denmark
[4] Nykobing F Hosp, Ctr Epidemiol Res, Ejegodvej 63, DK-4800 Nykobing, Denmark