Acknowledgments The project group Bergen in change (BiE) contributed to the study design. The group consists of Silje Mæland, Lars Thore Fadnes, William Hazell, Stine Lehmann, Øystein Vedaa, Jens Christoffer Skogen, Gro Mjeldheim Sandal, Ellen Haug, Ragnhild Bjørknes, Åsgeir Kjetland Rabben and Andreas Roaldsnes. We would like to thank Guri Rørtveit and Øystein Hetlevik from the University of Bergen, Kjell Wolff and Trond Egil Hansen from Bergen Municipality for initiating this work in the frame of Alrek Health Cluster, Sverre Littleskare for advice on setting up and cohort during the pandemic, and Stina Johansson at Rambøll Consulting for technical support. The data Protection Officers at University of Bergen and Bergen Municipality contributed with important guidance, and the Norwegian Regional Committee for Ethics in Medical Research for fast-tracking COVID-19 projects.