Endotoxin exposure and inflammation markers among agricultural workers in Colorado and Nebraska.
The adverse respiratory effects of agricultural dust inhalation are mediated in part by endotoxin, a constituent of gram-negative bacterial cell walls. This study quantified personal work-shift exposures to inhalable dust, endotoxin, and its reactive 3-hydroxy fatty acid (3-OHFA) constituents among workers in grain elevators, cattle feedlots, dairies, and on corn farms. Exposures were compared with post-work-shift nasal lavage fluid inflammation markers and respiratory symptoms. Breathing-zone personal air monitoring was performed over one work shift to quantify inhalable dust (Institute of Medicine samplers), endotoxin (recombinant factor C [rFC] assay), and 3-OHFA (gas chromatography/mass spectrometry). Post-shift nasal lavage fluids were assayed for polymorphonuclear neutrophils (PMN), myeloperoxidase (MPO), interleukin 8 (IL-8), albumin, and eosinophilic cation protein (ECP) concentrations. The geometric mean (GSD) of endotoxin exposure (rFC assay) among the 125 male participants was 888 +/- (6.5) EU/m(3), and 93% exceeded the proposed exposure limit (50 EU/m(3)). Mean PMN, MPO, albumin, and ECP levels were two- to threefold higher among workers in the upper quartile of 3-OHFA exposure compared to the lowest exposure quartile. Even numbered 3-OHFA were most strongly associated with nasal inflammation. Symptom prevalence was not elevated among exposed workers, possibly due to endotoxin tolerance or a healthy worker effect in this population. This is the first study to evaluate the relationship between endotoxin's 3-OHFA constituents in agricultural dust and nasal airway inflammation. More research is needed to characterize the extent to which these agents contribute to respiratory disease among agricultural workers.
Burch
James B
JB
Department of Epidemiology and Biostatistics, Cancer Prevention and Control Program, and Center for Colon Cancer Research, University of South Carolina, Columbia, SC 29208, USA. burch@mailbox.sc.edu
Svendsen
Erik
E
Siegel
Paul D
PD
Wagner
Sara E
SE
von Essen
Susanna
S
Keefe
Thomas
T
Mehaffy
John
J
Martinez
Angelica Serrano
AS
Bradford
Mary
M
Baker
Laura
L
Cranmer
Brian
B
Saito
Rena
R
Tessari
John
J
Linda
Prinz
P
Andersen
Colene
C
Christensen
Opal
O
Koehncke
Niels
N
Reynolds
Stephen J
SJ
D000293:Adolescent; D000328:Adult; D000368:Aged; D000383:Agriculture; D000395:Air Pollutants, Occupational / Q000009:adverse effects*; D000418:Albumins / Q000032:analysis; D003120:Colorado; D004391:Dust; D004731:Endotoxins / Q000009:adverse effects*; D047150:Eosinophil Cationic Protein / Q000032:analysis; D006801:Humans; D007249:Inflammation / Q000139:chemically induced*; D016209:Interleukin-8 / Q000032:analysis; D008297:Male; D008875:Middle Aged; D017817:Nasal Lavage Fluid / Q000737:chemistry / Q000166:cytology; D009329:Nebraska; D009504:Neutrophils; D016273:Occupational Exposure / Q000009:adverse effects*; D009195:Peroxidase / Q000378:metabolism; D055815:Young Adult
D000395:Air Pollutants, Occupational; D000418:Albumins; D004391:Dust; D004731:Endotoxins; D016209:Interleukin-8; D009195:Peroxidase; D047150:Eosinophil Cationic Protein