IL6 and asthma: The b-coefficient for any of the associations between cytokines, lung function, sickness behaviour, asthma-related quality of life and self-rated health changed with less than 5% after including corticosteroids or LTRA treatment, respectively, in the model, apart from the association between quartile 4 compared to quartile 1 of IL-6 and sickness behaviour, which was strengthened by 16% after including ICS treatment.