Endotoxin exposure and respiratory symptoms in the cotton textile industry

One hundred fourteen male employees of a cotton spinning mill in western Germany participated in a cross-sectional study, the purpose of which was to clarify the dose effect of endotoxin exposure on respiratory symptoms. Airborne endotoxin exposures were classified as low (less than or equal to 100 endotoxin units [EU]/m(3)), medium (> 100-450 EU/m(3)), or high (> 450 EU/m(3)), on the basis of endotoxin activity in the Limulus amoebocyte lysate assay. Age- and smoking-adjusted odds ratios (ORs) and confidence intervals (Cls) were estimated. The dose-response relationship between current endotoxin exposure and prevalence of wheezing (medium: OR = 2.15, 95% Cl = 0.48-9.62; high: OR = 5.49, 95% Cl = 1.17-25.81) and cough (medium: OR = 2.11; 95% Cl = 0.59-7.56; high: OR = 3.93; 95% Cl = 1.02-15.12) was significant (test for linear trend: p values = 0.020 and 0.040, respectively). The association between exposure and wheezing was stronger among atopic workers. The higher prevalence of chest tightness and shortness of breath among workers with medium and high current endotoxin exposure did not reach statistical significance. The results suggested that there was a dose-dependent increase in bronchial symptoms, with significant effects occurring at exposures that exceeded 450 EU/m(3).