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Occupational endotoxin exposure reduces the risk of atopic sensitization but increases the risk of bronchial hyperresponsiveness.
Int Arch Allergy Immunol. 2010; 152(2):151-8.IA

Abstract

BACKGROUND

Microbial exposures in both childhood and adult life are protective against atopy, allergic rhinitis and atopic asthma. In adults, this protective effect is paralleled by an increased prevalence of non-atopic asthma. This study was undertaken to investigate associations between occupational endotoxin exposure and atopic sensitization and bronchial hyperresponsiveness to methacholine (BHR) in agricultural workers. In addition, the role of atopy in endotoxin-related respiratory effects was studied.

METHODS

Data were available for 427 farmers and agricultural industry workers, for whom airborne endotoxin exposure levels were estimated by 249 personal exposure measurements. Atopy was assessed as specific serum IgE to common inhalant allergens, and respiratory symptoms and personal characteristics by standardized questionnaires. BHR was determined in a subset of 113 subjects. Associations were adjusted for age, sex, smoking and living on a farm during childhood.

RESULTS

Endotoxin exposure was positively associated with BHR and wheeze (p < 0.05). In contrast, endotoxin exposure was inversely associated with atopy and IgE to grass pollen (p < 0.001). The proportions of wheeze and BHR that were attributable to atopy were only 16.6 and 32.8%, respectively.

CONCLUSIONS

High endotoxin exposure is a risk factor for BHR and wheeze, which were characterized by a predominantly non-atopic phenotype. At the same time, endotoxin exposure is related to a reduced risk of atopy and IgE to grass pollen in adults. It is unlikely that this is entirely a result of healthy worker selection, as significant inverse associations between endotoxin and IgE to grass pollen were found regardless of reported allergic symptoms.

Authors+Show Affiliations

Institute for Risk Assessment Sciences, Division of Environmental Epidemiology, Utrecht University, Utrecht, The Netherlands. L.A.Smit@uu.nlNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

20016197

Citation

Smit, Lidwien A M., et al. "Occupational Endotoxin Exposure Reduces the Risk of Atopic Sensitization but Increases the Risk of Bronchial Hyperresponsiveness." International Archives of Allergy and Immunology, vol. 152, no. 2, 2010, pp. 151-8.
Smit LA, Heederik D, Doekes G, et al. Occupational endotoxin exposure reduces the risk of atopic sensitization but increases the risk of bronchial hyperresponsiveness. Int Arch Allergy Immunol. 2010;152(2):151-8.
Smit, L. A., Heederik, D., Doekes, G., Lammers, J. W., & Wouters, I. M. (2010). Occupational endotoxin exposure reduces the risk of atopic sensitization but increases the risk of bronchial hyperresponsiveness. International Archives of Allergy and Immunology, 152(2), 151-8. https://doi.org/10.1159/000265536
Smit LA, et al. Occupational Endotoxin Exposure Reduces the Risk of Atopic Sensitization but Increases the Risk of Bronchial Hyperresponsiveness. Int Arch Allergy Immunol. 2010;152(2):151-8. PubMed PMID: 20016197.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Occupational endotoxin exposure reduces the risk of atopic sensitization but increases the risk of bronchial hyperresponsiveness. AU - Smit,Lidwien A M, AU - Heederik,Dick, AU - Doekes,Gert, AU - Lammers,Jan-Willem J, AU - Wouters,Inge M, Y1 - 2009/12/16/ PY - 2009/06/02/received PY - 2009/08/11/accepted PY - 2009/12/18/entrez PY - 2009/12/18/pubmed PY - 2010/6/25/medline SP - 151 EP - 8 JF - International archives of allergy and immunology JO - Int Arch Allergy Immunol VL - 152 IS - 2 N2 - BACKGROUND: Microbial exposures in both childhood and adult life are protective against atopy, allergic rhinitis and atopic asthma. In adults, this protective effect is paralleled by an increased prevalence of non-atopic asthma. This study was undertaken to investigate associations between occupational endotoxin exposure and atopic sensitization and bronchial hyperresponsiveness to methacholine (BHR) in agricultural workers. In addition, the role of atopy in endotoxin-related respiratory effects was studied. METHODS: Data were available for 427 farmers and agricultural industry workers, for whom airborne endotoxin exposure levels were estimated by 249 personal exposure measurements. Atopy was assessed as specific serum IgE to common inhalant allergens, and respiratory symptoms and personal characteristics by standardized questionnaires. BHR was determined in a subset of 113 subjects. Associations were adjusted for age, sex, smoking and living on a farm during childhood. RESULTS: Endotoxin exposure was positively associated with BHR and wheeze (p < 0.05). In contrast, endotoxin exposure was inversely associated with atopy and IgE to grass pollen (p < 0.001). The proportions of wheeze and BHR that were attributable to atopy were only 16.6 and 32.8%, respectively. CONCLUSIONS: High endotoxin exposure is a risk factor for BHR and wheeze, which were characterized by a predominantly non-atopic phenotype. At the same time, endotoxin exposure is related to a reduced risk of atopy and IgE to grass pollen in adults. It is unlikely that this is entirely a result of healthy worker selection, as significant inverse associations between endotoxin and IgE to grass pollen were found regardless of reported allergic symptoms. SN - 1423-0097 UR - https://www.unboundmedicine.com/medline/citation/20016197/Occupational_endotoxin_exposure_reduces_the_risk_of_atopic_sensitization_but_increases_the_risk_of_bronchial_hyperresponsiveness_ L2 - https://www.karger.com?DOI=10.1159/000265536 DB - PRIME DP - Unbound Medicine ER -