Respiratory Effects of Bioaerosols: Exposure–Response Study Among Salmon-Processing Workers Olga Shiryaeva, MD, PhD, 1,2 Lisbeth Aasmoe, PhD, 2,3 Bjørn Straume, MD, PhD, 1 Ann-Helen Olsen, MSc, 2 Arild Øvrum, MSc, 2 Eva Kramvik, MSc, 2 Merethe Larsen, MSc, 2 Anne Renstrøm, PhD, 4,5 Anne-Sophie Merritt, MD, PhD, 4,5 Kari Kulvik Heldal, PhD, 6 and Berit Elisabeth Bang, PhD 2,3 Objectives The aim of the study was to determine exposure–response relationships in salmon-processing workers. Methods Cross-shift FEV1, acute respiratory symptoms, and exposure to total protein, parvalbumin and endotoxin were main variables measured during one workweek. Exposure–response relationships were analyzed by Generalized Estimation Equations of cross-week data and by multiple regressions of day-to-day data. Results Exposure levels were higher in those workers who reported use of water hose. GEE showed negative coefficients for interaction between TP exposure and time (days) on cross-week change of FEV1. Multiple regressions showed significant associations between TP levels and cross-shift change of FEV1 and symptoms (cough, chest tightness) only for Monday shifts. Conclusions A tolerance effect during the course of a workweek is suggested. Use of water hose is a risk process with regard to the liberation of measured components of bioaerosols. Am. J. Ind. Med. 57:276–285, 2014. ß 2013 Wiley Periodicals, Inc. KEY WORDS: bioaerosols; exposure–response; tolerance; respiratory symptoms; lung function INTRODUCTION Work in seafood industry involves inhalation exposure to bioaerosols. The components of the bioaerosols depend on the processes performed and on what seafood tissues are exposed to the air [Jeebhay et al., 2004, 2005]. Inhalation of airborne particles during seafood processing has been demonstrated as a potential risk for sensitization, respiratory symptoms, bronchial hyperresponsiveness, and work-related asthma [Sherson et al., 1989; Malo and Cartier, 1993; Douglas et al., 1995; Bonlokke et al., 2004; Bang et al., 2005; Jeebhay et al., 2008]. It has been shown that workers engaged in seafood processing are exposed to proteins, allergens, as well as endotoxins [Sherson et al., 1989; Bang et al., 2005; Jeebhay et al., 2005]. Several epidemiological studies have been performed among seafood industry worker populations to evaluate symptoms and lung function, but there is a lack of 1 FacultyofHealthSciences,DepartmentofCommunityMedicine,UniversityofTromsÖ, TromsÖ,Norway 2 Department of Occupational and Environmental Medicine, University Hospital North Norway,TromsÖ,Norway 3 FacultyofHealthScience,MedicalPharmacologyandToxicology,DepartmentofMed- ical Biology,Universityof TromsÖ,TromsÖ,Norway 4 Institute of Environmental Medicine,Karolinska Institute, Stockholm, Sweden 5 Centre of occupational and environmental medicine, Stockholm County Council, Stockholm,Sweden 6 National Institute of Occupational Health,Oslo,Norway Contractgrantsponsor:NorthernNorwayRegionalHealthAuthority(HelseNordRHF), Norway. Disclosure Statement:The authors report no conflicts ofinterests.  Correspondence to: Olga Shiryaeva,Department of Occupational and Environmental Medicine,University Hospital North Norway,Sykehusveien 38,TromsÖ 9038,Norway. E-mail:olga.shiryaeva@uit.no Accepted 25 October 2013 DOI10.1002/ajim.22281.Publishedonline 6 December 2013inWiley Online Library (wileyonlinelibrary.com). AMERICAN JOURNAL OF INDUSTRIAL MEDICINE 57:276–285 (2014) ß 2013 Wiley Periodicals, Inc.