1 Serum perfluoroalkyl substances (PFAS) and risk of asthma and various allergies in adolescents. The Tromsø study Fit Futures in Northern Norway. Maria Averina a,b , Jan Brox a c , Sandra Huber a , Anne-Sofie Furberg b,d , Martin Sørensen e,f a Department of Laboratory Medicine, University Hospital of North Norway, 9038 Tromsø, Norway b Department of Community Medicine, UiT The Arctic University of Norway, Tromsø, Norway c Department of Medical Biology, UiT The Arctic University of Norway, Tromsø, Norway d Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway e Department of Pediatric and Adolescent medicine, University Hospital of North Norway, Tromsø, Norway f Pediatric Research Group, Department of Clinical Medicine, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway Corresponding author: Maria Averina, Department of Laboratory Medicine, University Hospital of North Norway, 9038 Tromsø, Norway. E-mail: maria.averina@unn.no