Collaborations The principal investigator for this project Ass Prof Maria Åberg is the chair of the steering committee for Physical Fitness and Brain Epidemiological studies (PHYSBE) which is a multidisciplinary umbrella organization for several projects. Prof Kjell Torén from Occupational and Environmental Medicine provides epidemiological competence. Prof Margda Waern provides psychiatric expertise. Physiotherapist Louise Danielsson and Prof Kristian Bolin at the Department of Economics and Statistics have experience of clinical intervention studies.