The study of occupational risk factors and interventions for baker's allergy and asthma among supermarket bakery workers

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dc.contributor.advisorJeebhay, Mohamed Fareeden_ZA
dc.contributor.advisorHeederik, Dicken_ZA
dc.contributor.advisorMeijster, Timen_ZA
dc.contributor.authorBaatjies, Roslynnen_ZA
dc.date.accessioned2014-11-08T08:06:42Z
dc.date.available2014-11-08T08:06:42Z
dc.date.issued2013en_ZA
dc.descriptionIncludes abstract.en_ZA
dc.descriptionIncludes bibliographical references.en_ZA
dc.description.abstractBackground: Baker's asthma is the most serious manifestation of occupational allergy among bakery workers. It is caused by IgE-mediated sensitisation and subsequent allergic reaction in the airways to specific occupational airborne allergens in flour or baking ingredients. Major aims of this study were to: characterise asthma phenotypes and environmental exposure to flour allergens among bakers and modifying factors; study associations between phenotype and environmental exposure and identify potential modifying factors of this association; determine the effectiveness of specific interventions in reducing exposure and the risk of sensitisation or allergic respiratory disease. Methods: A cross-sectional study was conducted among 517 bakery workers employed in 31 supermarkets. Health outcomes were assessed using a standardized questionnaire, immunological tests (sIgE, sIgG), methacholine challenge test and fractional exhaled nitric oxide (FeNO). Exposure assessment conducted pre- and post-intervention entailed determination of inhalable concentration of particulate mass and specific allergen levels. The intervention employed a group-randomised design to evaluate dust control measures. Results: Prevalence of probable occupational asthma (POA, 13%) was higher than atopic (AA, 6%), non-atopic (NAA, 6%) and work-aggravated asthma (WAA, 3%). Sensitisation to flour allergens was a major determinant of elevated FeNO among bakers. Bread bakers had the highest dust particulate (mean = 1.33 mg/m3) and allergen exposures. Exposure response relationships followed a bell-shaped curve, with the prevalence of IgE- sensitisation, allergic symptoms and POA, increasing up to 10-15 μg/m3 of airborne wheat allergen concentrations before declining. The association for IgE sensitization was not modified by IgG4 to wheat. The overall effect of the intervention revealed a 50% decrease in mean flour dust, wheat allergen and rye exposures in bakeries. Conclusion: Occupational asthma is the most common phenotype among supermarket bakery workers, with sensitisation to cereal flour allergens being the main determinant of allergic airway inflammation. The bell-shaped exposure response relationship is not modified by the presence of blocking antibodies and is probably due to a healthy worker effect. The multi-pronged intervention strategy was effective in reducing airborne flour dust and allergen levels. It is recommended that further studies investigate the long term health impact of these interventions in reducing the disease burden.en_ZA
dc.identifier.apacitationBaatjies, R. (2013). <i>The study of occupational risk factors and interventions for baker's allergy and asthma among supermarket bakery workers</i>. (Thesis). University of Cape Town ,Faculty of Health Sciences ,Department of Public Health and Family Medicine. Retrieved from http://hdl.handle.net/11427/9381en_ZA
dc.identifier.chicagocitationBaatjies, Roslynn. <i>"The study of occupational risk factors and interventions for baker's allergy and asthma among supermarket bakery workers."</i> Thesis., University of Cape Town ,Faculty of Health Sciences ,Department of Public Health and Family Medicine, 2013. http://hdl.handle.net/11427/9381en_ZA
dc.identifier.citationBaatjies, R. 2013. The study of occupational risk factors and interventions for baker's allergy and asthma among supermarket bakery workers. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Baatjies, Roslynn AB - Background: Baker's asthma is the most serious manifestation of occupational allergy among bakery workers. It is caused by IgE-mediated sensitisation and subsequent allergic reaction in the airways to specific occupational airborne allergens in flour or baking ingredients. Major aims of this study were to: characterise asthma phenotypes and environmental exposure to flour allergens among bakers and modifying factors; study associations between phenotype and environmental exposure and identify potential modifying factors of this association; determine the effectiveness of specific interventions in reducing exposure and the risk of sensitisation or allergic respiratory disease. Methods: A cross-sectional study was conducted among 517 bakery workers employed in 31 supermarkets. Health outcomes were assessed using a standardized questionnaire, immunological tests (sIgE, sIgG), methacholine challenge test and fractional exhaled nitric oxide (FeNO). Exposure assessment conducted pre- and post-intervention entailed determination of inhalable concentration of particulate mass and specific allergen levels. The intervention employed a group-randomised design to evaluate dust control measures. Results: Prevalence of probable occupational asthma (POA, 13%) was higher than atopic (AA, 6%), non-atopic (NAA, 6%) and work-aggravated asthma (WAA, 3%). Sensitisation to flour allergens was a major determinant of elevated FeNO among bakers. Bread bakers had the highest dust particulate (mean = 1.33 mg/m3) and allergen exposures. Exposure response relationships followed a bell-shaped curve, with the prevalence of IgE- sensitisation, allergic symptoms and POA, increasing up to 10-15 μg/m3 of airborne wheat allergen concentrations before declining. The association for IgE sensitization was not modified by IgG4 to wheat. The overall effect of the intervention revealed a 50% decrease in mean flour dust, wheat allergen and rye exposures in bakeries. Conclusion: Occupational asthma is the most common phenotype among supermarket bakery workers, with sensitisation to cereal flour allergens being the main determinant of allergic airway inflammation. The bell-shaped exposure response relationship is not modified by the presence of blocking antibodies and is probably due to a healthy worker effect. The multi-pronged intervention strategy was effective in reducing airborne flour dust and allergen levels. It is recommended that further studies investigate the long term health impact of these interventions in reducing the disease burden. DA - 2013 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2013 T1 - The study of occupational risk factors and interventions for baker's allergy and asthma among supermarket bakery workers TI - The study of occupational risk factors and interventions for baker's allergy and asthma among supermarket bakery workers UR - http://hdl.handle.net/11427/9381 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/9381
dc.identifier.vancouvercitationBaatjies R. The study of occupational risk factors and interventions for baker's allergy and asthma among supermarket bakery workers. [Thesis]. University of Cape Town ,Faculty of Health Sciences ,Department of Public Health and Family Medicine, 2013 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/9381en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Public Health and Family Medicineen_ZA
dc.publisher.facultyFaculty of Health Sciencesen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherPublic Health and Family Medicineen_ZA
dc.titleThe study of occupational risk factors and interventions for baker's allergy and asthma among supermarket bakery workersen_ZA
dc.typeDoctoral Thesis
dc.type.qualificationlevelDoctoral
dc.type.qualificationnamePhDen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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