Association between depression, lung function and inflammatory markers in patients with asthma and occupational asthma

Objective: Depression is associated with autonomic and immune dysregulation, yet this remains poorly explored in asthma. We assessed associations between depressive disorder, lung function, and inflammatory markers in patients under investigation for occupational asthma (OA). Methods: 112 patients under investigation for OA (60% men) underwent a psychiatric interview to assess depressive disorder, and spirometry, a methacholine test, sputum induction and specific inhalation challenge (SIC) to assess OA. Blood and sputum inflammatory markers were assessed. Results: There was a statistically significant association between depressive disorder (p=.0195) and FEV1 responses, with the drop in FEV1 post-SIC smaller in patients with OA and depression, versus OA with no depression, (p < .001). Conclusions: The presence of depressive disorder may influence FEV1 in patients with OA, which may be via autonomic pathways. However, further studies are warranted in order to determine the mechanisms which underlie these effects.