title: Surfactant protein-D and exposure to bioaerosols in wastewater and garbage workers.
abstract: OBJECTIVE
  Bioaerosols and their constituents, such as endotoxins, are capable of causing an inflammatory reaction at the level of the lung-blood barrier, which becomes more permeable. Thus, it was hypothesized that occupational exposure to bioaerosols can increase leakage of surfactant protein-D (SP-D), a lung-specific protein, into the bloodstream.
  
  
  METHODS
  SP-D was determined by ELISA in 316 wastewater workers, 67 garbage collectors, and 395 control subjects. Exposure was assessed with four interview-based indicators and by preliminary endotoxin measurements using the Limulus amoebocyte lysate assay. Influence of exposure on serum SP-D was assessed by multiple linear regression considering smoking, glomerular function, lung diseases, obesity, and other confounders.
  
  
  RESULTS
  Overall, mean exposure levels to endotoxins were below 100 EU/m(3). However, special tasks of wastewater workers caused higher endotoxin exposure. SP-D concentration was slightly increased in this occupational group and associated with the occurrence of splashes and contact to raw sewage. No effect was found in garbage collectors. Smoking increased serum SP-D. No clinically relevant correlation between spirometry results and SP-D concentrations appeared.
  
  
  CONCLUSIONS
  These results support the hypothesis that inhalation of bioaerosols, even at low concentrations, has a subclinical effect on the lung-blood barrier, the permeability of which increases without associated spirometric changes.
authors.affiliation: Occupational and Environmental Medicine Unit, University of Zurich, Med. Poliklinik USZ, Rämistrasse 100, 8091, Zurich, Switzerland.
authors.forename: R
authors.initials: R
authors.lastname: Daneshzadeh Tabrizi
authors.forename: A
authors.initials: A
authors.lastname: Bernard
authors.forename: A M
authors.initials: AM
authors.lastname: Thommen
authors.forename: F
authors.initials: F
authors.lastname: De Winter
authors.forename: A
authors.initials: A
authors.lastname: Oppliger
authors.forename: S
authors.initials: S
authors.lastname: Hilfiker
authors.forename: A
authors.initials: A
authors.lastname: Tschopp
authors.forename: P
authors.initials: P
authors.lastname: Hotz
mesh_terms: D000328:Adult; D000336:Aerosols / Q000009:adverse effects* / Q000032:analysis; D016022:Case-Control Studies; D004391:Dust / Q000032:analysis; D004731:Endotoxins / Q000009:adverse effects / Q000032:analysis; D004784:Environmental Monitoring / Q000379:methods; D004797:Enzyme-Linked Immunosorbent Assay; D062665:Epidemiological Monitoring; D005260:Female; D005735:Garbage; D006801:Humans; D007407:Interviews as Topic; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects* / Q000032:analysis; D009790:Occupations / Q000145:classification / Q000706:statistics & numerical data; D037663:Pulmonary Surfactant-Associated Protein D / Q000097:blood*; D018570:Risk Assessment; D012307:Risk Factors; D012722:Sewage / Q000009:adverse effects / Q000032:analysis; D012907:Smoking / Q000009:adverse effects / Q000453:epidemiology; D013557:Switzerland / Q000453:epidemiology; D014865:Waste Disposal, Fluid; D055815:Young Adult
chemical_list: D000336:Aerosols; D004391:Dust; D004731:Endotoxins; D037663:Pulmonary Surfactant-Associated Protein D; D012722:Sewage