Endotoxin is a cell wall component from Gram-negative bacteria, and inhaled endotoxin contributes significantly to the induction of airway inflammation and dysfunction. Background levels of endotoxin have not yet been extensively described. In this study, airborne endotoxin was measured with a standardized protocol in 5 types of background environment (169 samples) in Denmark from October to May. Endotoxin levels in a greenhouse (median = 13.2 EU/m3) were significantly higher than in the other environments. The air from biofuel plants (median = 5.3 EU/m3), the air on congested streets (median = 4.4 EU/m3) and on an agricultural field (median = 2.9 EU/m3) had higher endotoxin contents than the air in industrial areas (median = 1.3 EU/m3) or in towns (median = 0.33 EU/m3). Levels in industrial areas were significantly higher than in towns. A literature study revealed background levels of endotoxin on different continents between 0.063-410 EU/m3, with median or mean values between 0.063-3.6 EU/m3. Endotoxin concentrations in towns and industrial areas were higher in April and May than in autumn and winter, and were higher in October than in winter. These data of exposure in background environments and of seasonal variation are helpful for public health practitioners, epidemiologists and industrial hygienists.
Allergy to indoor allergens can cause frequent and severe health problems in children. Because little is known about the content of allergens in the indoor environments in Norway, we wanted to assess the levels of cat, dog and mite allergens in schools and day-care centers in Oslo. Allergen levels in dust samples from 155 classrooms and 81 day-care units were measured using commercially available enzyme-linked immunosorbent assay (ELISA) kits. Additionally, we measured the levels of endotoxin in 31 day-care units, using the limulus amebocyte lysate test. Most of the dust samples contained detectable amounts of cat and dog allergens. In mattress and floor dust (day-care centers), and curtain and floor dust (schools) the median Fel d 1 levels were 0.17, 0.002, 0.02 and 0.079 microg/m2, while the median Can f 1 levels were 1.7, 0.03, 0.1 and 0.69 microg/m2, respectively. Levels of cat and dog allergens in school floor dust were associated with the number of pupils with animals at home. In contrast,
Knowledge of the effects of domestic endotoxin on children's lung function is limited. The association between domestic endotoxin and asthma or wheeze and lung function among school-age children (six to 18 years of age) was examined. The interaction between endotoxin and other personal and environmental characteristics and lung function was also assessed.
A case-control study was conducted in and around the rural community of Humboldt, Saskatchewan, between 2005 and 2007. Parents of cases reported either doctor-diagnosed asthma or wheeze in the previous year. Controls were randomly selected from those not reporting these conditions. Data were collected by questionnaire to ascertain symptoms and conditions, while spirometry was used to measure lung function including forced vital capacity and forced expiratory volume in 1 s. Dust collected from the child's play area floor and the child's mattress was used to quantify endotoxin, and saliva was collected to quantify cotinine levels and assess tobacco smoke exposure.
There were 102 cases and 207 controls included in the present study. Lower forced expiratory volume in 1 s was associated with higher mattress endotoxin load among female cases (beta=-0.25, SE=0.07 [P
Cites: Am J Respir Cell Mol Biol. 2000 May;22(5):604-1210783133
We have studied cross-shift respiratory responses of several individual bioaerosol components of the dust in the grain and feed industry in Norway.
Cross-shift changes in lung function and nasal congestion, as well as in respiratory and systemic symptoms of 56 exposed workers and 36 referents, were recorded on the same day as full-shift exposure to the inhalable aerosol fraction was assessed. Exposure-response associations were investigated by regression analysis.
The workers were exposed on average to 1.0 mg/m(3) of grain dust, 440 EU/m(3) of endotoxin, 6 ?g/m(3) of ?-1,3-glucans, 17?10(4)/m(3) of bacteria and 4?10(4)/m(3) of fungal spores during work. The exposure was associated with higher prevalence of self-reported eye and airway symptoms, which were related to the individual microbial components in a complex manner. Fatigue and nose symptoms were strongest associated with fungal spores, cough with or without phlegm was associated with grain dust and fungal spores equally strong and wheeze/tight chest/dyspnoea was strongest associated with grain dust. Bioaerosol exposure did not lead to cross-shift lung function decline, but several microbial components had influence on nose congestion.
Exposure to fungal spores and dust showed stronger associations with respiratory symptoms and fatigue than endotoxin exposure. The associations with dust suggest that there are other components in dust than the ones studied that induce these effects.
Cites: J Occup Environ Med. 2008 Dec;50(12):1394-40019092495
Cites: Occup Environ Med. 2003 Jun;60(6):444-5012771397
Cites: Br J Ind Med. 1984 Feb;41(1):94-96691942
Cites: Eur Respir J. 2001 Nov;18(5):770-911757626
Cites: Chest. 1996 Jul;110(1):263-708681637
Cites: Occup Environ Med. 1997 Jul;54(7):457-659282120
Cites: Ann Occup Hyg. 2012 Aug;56(7):776-8822553153
Cites: Scand J Work Environ Health. 2002 Aug;28(4):256-6312199427
Cites: Ann Occup Hyg. 2013 Nov;57(9):1105-1423813889
Cites: Environ Health Perspect. 1986 Apr;66:73-803709486
Cites: Am J Epidemiol. 1992 Nov 15;136(10):1269-791476149
Cites: Appl Occup Environ Hyg. 2001 Jun;16(6):685-9711414519
Cites: Eur Respir J. 2005 Oct;26(4):720-3516204605
Cites: Am Rev Respir Dis. 1991 Dec;144(6):1314-211741544
Cites: Ann Occup Hyg. 2015 Jul;59(6):724-3625743566
Cites: Chest. 2004 Apr;125(4):1394-915078751
Cites: Occup Environ Med. 1998 May;55(5):349-559764113
Cites: Eur Respir J. 2005 Aug;26(2):319-3816055882
Cites: J Occup Environ Med. 2015 Sep;57(9):1004-826340289
Cites: Am Rev Respir Dis. 1983 Sep;128(3):399-4046614633
An increased prevalence of respiratory problems among softwood lumber mill workers has been observed in a number of studies. These workers are potentially exposed to a variety of respiratory hazards including wood dust, abietic or other resin acids, monoterpenes, and fungi, as well as endotoxins. The objectives of this study were to determine if lumber mill workers were exposed to hazardous levels of airborne endotoxin and to identify the factors contributing to high exposures. Personal endotoxin samples (n = 216) were collected in four lumber mills in the Canadian province of British Columbia. The mean personal exposure concentration was 2.09 ng/m.(3) and 9% of the samples were above 5 ng/m.(3). Factors related to the personal endotoxin exposure were type of job, use of compressed air, the percentage of time spent in a booth or cab during a shift, and dust concentration. Log storage practices were also suspected of playing a role. The levels of exposure observed in this study were low compared to the levels reported for populations with respiratory problems attributed to endotoxins.
Studies describing respiratory health hazards for workers in swine production facilities have been published in the United States, Sweden, Canada, the Netherlands, and Denmark. Up to 50% of these workers experience bronchitis, organic dust toxic syndrome, hyper-reactive airways disease, chronic mucous membrane irritation, and other respiratory effects. These studies clearly point to the fact that this occupational environment poses a significant health risk hazard, and that control methods are needed to protect the worker. Before precise control strategies can be developed, implemented, and evaluated, dose-response studies are required to determine acceptable target levels for exposure. A previous manuscript described the development of multiple regression equations characterizing the relationships between environmental exposures and pulmonary response in a cohort of 207 swine producers. Baseline pulmonary function was included as a significant predictor of cross-shift decrements in pulmonary function in addition to personal measurements of dust, endotoxin, and ammonia concentrations. These equations were then used to predict specific exposure levels of dust and ammonia that could be expected to elicit significant decrements in cross-shift pulmonary function. This paper presents the results from analysis of follow-up data obtained on this same cohort 2 years after the initial measurements. At the second measurement period of the study (time-2), swine workers were found to have a mean cross-shift decrease in FEV1 of 2%. Cross-shift change in FEV1 was significantly correlated with personal exposures to total dust, total endotoxin, respirable endotoxin, and ammonia. The magnitude of the decrease in FEV1 was associated with increasing airborne concentrations of these environmental parameters thus confirming the dose-response relationship observed in the initial study (time-1). The correlation of dust with FEV1 changes in workers with more than 6 years of exposure (time-1 data) and more than 10 years of exposure (time-2 data) suggests that dust exposure is an important factor in chronic respiratory disease. Additionally, the correlation of endotoxins with FEV1 changes in the group with less than 6 years exposure (time-2 data) suggests endotoxins may have more significance for subacute respiratory effects. The agreement between observed cross-shift FEV1 changes measured in time-2 with changes predicted using regression equations derived from time-1 data demonstrates a consistent dose-response relationship over time for this cohort of swine production workers. This finding provides further support for conclusions of the previous study that levels of 2.5 mg/m3 (total dust) and 7.5 ppm (ammonia) are reasonable guidelines for occupational exposure limits in this environment.
Swine confinement buildings are known to contain large concentrations of airway irritants, and a number of studies have shown acute inflammatory effects in previously unexposed subjects when introduced to the environment in such buildings. However, studies comparing different methods of assessing such reactions are lacking, and it is not known if a measurable response could be found at lower exposure rates. The purpose of this study was to investigate exposure levels in a Norwegian swine confinement building, the airway response to such exposure, and to compare invasive and non-invasive methods of response measurement.
Twelve medical students who were previously unexposed to swine dust stayed in a swine confinement building in Norway for 4 hours, and underwent measurements before and after the start of exposure. The same measurements were also performed beforehand, on the same weekday without exposure, in such a manner that the subjects were their own controls.
The exposure assessment showed considerably lower concentrations of organic dust and endotoxin than earlier studies. However, small, but significant increases in markers of airway inflammation, were found.
Airway response can be measured after lower exposure to airborne irritants in swine confinement buildings than previously known. Further research is needed to assess whether this finding can be utilized for preventive purposes.