title: Occupational exposure levels of bioaerosol components are associated with serum levels of the acute phase protein Serum Amyloid A in greenhouse workers.
abstract: BACKGROUND
  Occupational exposure to particles may be associated with increased inflammation of the airways. Animal experiments suggest that inhaled particles also induce a pulmonary acute phase response, leading to systemic circulation of acute phase proteins. Greenhouse workers are exposed to elevated levels of bioaerosols. The objective of this study is to assess whether greenhouse workers personal exposure to bioaerosol components was associated with serum levels of the acute phase proteins Serum Amyloid A (SAA) and C-reactive protein (CRP).
  
  
  METHODS
  SAA and CRP levels were determined in serum sampled repeatedly from 33 greenhouse workers. Blood was drawn repeatedly on Mondays and Thursdays during work weeks. Acute phase protein levels were compared to levels in a comparison group of 42 people and related to individual exposure levels to endotoxin, dust, bacteria, fungi and β-glucan.
  
  
  RESULTS
  Serum levels of SAA and CRP were not significantly different in greenhouse workers and a reference group, or on the two work days. In a mixed model, SAA levels were positively associated with endotoxin exposure levels (p = 0.0007). Results for fungi were not clear. CRP levels were positively associated with endotoxin exposures (p = 0.022). Furthermore, when workers were categorized into three groups based on SAA and CRP serum levels endotoxin exposure was highest in the group with the highest SAA levels and in the group with middle and highest CRP levels. SAA and CRP levels were elevated in workers with asthma.
  
  
  CONCLUSIONS
  Greenhouse workers did not have elevated serum levels of SAA and CRP compared to a reference group. However, occupational exposure to endotoxin was positively associated with serum levels of the acute phase proteins SAA and CRP. Preventive measures to reduce endotoxin exposure may be beneficial.
authors.affiliation: National Research Centre for the Working Environment, Lersø Parkallé 105, DK-2100, Copenhagen, Denmark. amm@nrcwe.dk.
authors.forename: Anne Mette
authors.initials: AM
authors.lastname: Madsen
authors.affiliation: Research Unit for Occupational and Environmental Medicine, Institute of Clinical Research, University of Southern Denmark, DK-5000, Odense C, Denmark. tthilsing@health.sdu.dk.|Research Unit for General Practice, Department of Public Health, University of Southern Denmark, DK-5000, Odense C, Denmark. tthilsing@health.sdu.dk.
authors.forename: Trine
authors.initials: T
authors.lastname: Thilsing
authors.affiliation: Research Unit for Occupational and Environmental Medicine, Institute of Clinical Research, University of Southern Denmark, DK-5000, Odense C, Denmark. Jesper.Baelum@rsyd.dk.|Research Unit for General Practice, Department of Public Health, University of Southern Denmark, DK-5000, Odense C, Denmark. Jesper.Baelum@rsyd.dk.|OPEN, Odense Patient Exploratory Network, Institute of Clinical Research, SDU, Odense C, Denmark. Jesper.Baelum@rsyd.dk.
authors.forename: Jesper
authors.initials: J
authors.lastname: Bælum
authors.affiliation: National Research Centre for the Working Environment, Lersø Parkallé 105, DK-2100, Copenhagen, Denmark. ahg@nrcwe.dk.
authors.forename: Anne Helene
authors.initials: AH
authors.lastname: Garde
authors.affiliation: National Research Centre for the Working Environment, Lersø Parkallé 105, DK-2100, Copenhagen, Denmark. ubv@nrcwe.dk.
authors.forename: Ulla
authors.initials: U
authors.lastname: Vogel
mesh_terms: D000210:Acute-Phase Reaction / Q000097:blood*; D000328:Adult; D000382:Agricultural Workers' Diseases / Q000097:blood*; D000383:Agriculture; D000395:Air Pollutants, Occupational / Q000097:blood; D004784:Environmental Monitoring / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure / Q000032:analysis*; D000685:Serum Amyloid A Protein / Q000378:metabolism*
chemical_list: D000395:Air Pollutants, Occupational; D000685:Serum Amyloid A Protein