Assessing the health impact of interventions for baker’s allergy and asthma in supermarket bakeries: a group randomised trial

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To assess the impact of an intervention for baker’s allergy and asthma in supermarket bakeries.


A group randomised trial conducted in 31 bakeries (n = 337 bakers) that were randomly assigned to one of two intervention groups (n = 244 bakers) and a control group (n = 93 bakers). Health data collected prior to and 1-year after the intervention included information obtained from an ECRHS questionnaire; tests for atopy and serum-specific IgE to cereal flours; fractional exhaled nitric oxide (FeNO). Data from the two intervention groups were combined to form one intervention group for purposes of the statistical analysis.


At 1 year of follow-up, the incidence and level of decline of work-related ocular–nasal and chest symptoms, sensitisation status and elevated FeNO (FeNO > 25 ppb) was similar in both intervention and control groups. The mean FeNO difference was also similar across both groups (2.2 ppb vs 1.7 ppb, p = 0.86). In those with FeNO > 25 ppb at baseline, the decline was greater in the intervention compared to control group (16.9 ppb vs 7.7 ppb, p = 0.24). Multivariate logistic regression models (adjusting for smoking, baseline sensitisation to cereal flour, baseline FeNO > 25 ppb) did not demonstrate an appreciable FeNO decline (≥ 10%) in the intervention compared to control group. However, stratification by the presence of work-related ocular–nasal symptoms in bakers at baseline demonstrated a significant FeNO decline (≥ 10%) in the intervention compared to the control group (OR 3.73, CI 1.22–11.42).


This study demonstrates some evidence of an intervention effect on FeNO 1 year after an intervention, particularly in bakers with work-related ocular–nasal symptoms.

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We would like to acknowledge the special contribution of Dr Tanusha Singh of the National Institute for Occupational Health for the laboratory analysis, as well as research nurse assistants Dawn Venter and Faieza Desai from the Centre for Environmental and Occupational Health Research (CEOHR) for conducting the fieldwork. We would also like to acknowledge the staff and employees of the bakeries that contributed to the successful completion of this study.


There was no additional funding required for this sub-study. However, the data collection of the larger study was originally funded through research scholarship grants from the Center for Asthma in the Workplace (Montreal, Canada), South African Medical Research Council, National Research Foundation FA2006040700028 (Republic of South Africa), Fogarty International Centre (Bethesda, Maryland, USA)-National Institutes of Health (2 D43 TW000812-06), Allergy Society of South Africa (Cape Town) and University of Cape Town Research Committee (Cape Town) and the baking industry (Cape Town). The funders had no role in study design; in the collection, analysis and interpretation of the data; in the writing of the report; and in the decision to submit the paper for publication. The contents of this publication are solely the responsibility of the authors and do not necessarily reflect the official views of these agencies.

Author information

MFJ was responsible for the overall conceptualisation and design of the study, ensuring the development of the intervention. RB was responsible for overseeing the fieldwork, data management and analysis. FM was responsible for conducting the data analysis and preparing the manuscript under the supervision of MFJ and RB. All investigators contributed to and reviewed the manuscript prior to submission.

Correspondence to Mohamed F. Jeebhay.

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The authors declare that they have no competing interests.

Ethics approval

The original study received ethical approval from the Research Ethics Committee of the University of Cape Town (reference no. 272/2002). Informed consent was obtained from all study subjects as per the protocol. The protocol can be accessed on-line (!ApmArVMYxI4B4V-9TiBgKsTKGPMp).

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Al Badri, F.M., Baatjies, R. & Jeebhay, M.F. Assessing the health impact of interventions for baker’s allergy and asthma in supermarket bakeries: a group randomised trial. Int Arch Occup Environ Health (2020) doi:10.1007/s00420-019-01511-7

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  • Bakers
  • Allergy
  • Asthma
  • Exhaled nitric oxide
  • Workplace interventions