Occupational rhinitis and asthma in bakers: a cross-sectional study in the former Katanga province of DR Congo

OBJECTIVE

Bakers are at high risk of rhinitis and asthma, but the prevalence of these occupational diseases is not well known in Sub-Saharan Africa. We investigated the prevalence of occupational rhinitis and asthma among industrial bakers in the former province of Katanga.

METHODS

In a cross-sectional study conducted in eight towns from October 2018 to September 2019, we included 276 male workers from 18 industrial bakeries and 113 male controls (35 butchers and 78 bread sellers), all nonsmokers. Participants replied to a validated questionnaire (European Community of Respiratory Health Survey II), administered face to face, and performed spirometry at the work place. In 15 bakers with symptoms of work-related asthma, records of self-measured peak expiratory flow (PEF) 4 times per day during 4 weeks were analyzed by the OASYS (Occupational Asthma System) protocol.

RESULTS

The bakers and controls did not differ by age (32.2 ± 7.3 y vs 32.8 ± 10.3 y). According to the questionnaire, work-related rhinitis and asthma were significantly more prevalent among bakers (31% and 5%, respectively) than among controls (2% and 0%, respectively). However, the groups did not differ significantly with regard to spirometric parameters. Based on PEF records, 10 out of 15 were positive for occupational asthma (OASYS score > 2.5), so the rate of occupational asthma was 3.6% in this study.

CONCLUSION

This first study in DR Congo demonstrates the existence of occupational rhinitis and asthma among industrial bakers in Katanga. Further epidemiological studies are needed to clarify the extent and risk factors of baker's asthma in the area. In the meantime, advocacy and implementation of appropriate occupational hygiene measures are warranted to protect bakery workers in DR Congo.

Longitudinal predictors of bronchial hyperresponsiveness and FEV1 decline in bakers

OBJECTIVE

To determine long-term predictors of bronchial hyperresponsiveness (BHR) and forced expiratory volume in one second (FEV₁) decline.

METHODS

A longitudinal study in 110 bakers in 4 industrial bakeries and 38 non-exposed workers was conducted at the workplace with a mean of 3.3 visits per subject over a period of 13 years and a mean duration of follow-up of 6 years in bakers and 8 years in non-exposed subjects. A respiratory health questionnaire was administered; occupational allergen skin prick tests, spirometry and a methacholine bronchial challenge test were performed at each visit. In each bakery, full-shift dust samples of the inhalable fraction were obtained in order to assess the exposure of each job assignment. The repeated measurements of BHR and FEV₁ were analyzed using mixed effects logistic and linear regression models in subjects seen at least twice.

RESULTS

BHR, respiratory symptoms and their simultaneous occurrence depended on the duration of exposure. FEV₁ significantly decreased with duration of exposure and BHR at a preceding visit. This result persisted when adjusting for the effect of BHR at the current visit. The measured exposure levels were not a significant predictor for any outcome. Occupational sensitization was only a predictor of a decline in FEV₁ when duration of exposure was not included.

CONCLUSION

In flour-exposed industrial bakers, length of exposure and smoking are long-term determinants of BHR and of the decrease in FEV₁. BHR at a preceding visit predicted lower FEV₁ even when accounting for the effect of BHR at the current visit.

The effect of heat stress on hematological parameters and oxidative stress among bakery workers

Heat stress causes physiological changes, and changes in hematological parameters and hormonal levels in the human body, known as thermal strain. This study was conducted to determine the effect of exposure to heat stress on hematological parameters and oxidative stress in the bakers of Shahroud City, Iran. A total of 163 bakery workers (exposed group) and 135 office workers (unexposed group) with a minimum of 1-year working experience were selected. Exposure to heat stress was measured using ISO-7243 criteria on the hottest days of the year (late July and August). Wet-bulb globe temperature (WBGT) was calculated based on indoor environments. Oxidative stress indices including malondialdehyde (MDA), nitric oxide (NO), total antioxidant capacity (TAC) in the bakers' and office workers' serum and hematological parameters were measured. Statistical analysis was done through independent t-test, and multivariate linear regression using SPSS v24. Analysis of hematological parameters showed that about 70% and 68% of the bakers had abnormal mean cell volume (MCV) and white blood cell (WBC) count, respectively, while only around 12% of them had abnormal mean cell hemoglobin concentration (MCHC). The counts of red blood cells (RBC), WBC, lymphocytes (LYM), and MCV showed significant differences in different occupational groups (p < 0.05). The levels of MDA and NO were significantly higher in bakers with WBGT more than the threshold value (p < 0.05). The WBGT index for assessing heat stress can be used as a predictor variable for MDA and NO levels. In addition, heat stress exposure could be a risk factor for abnormal WBC, RBC, LYM, and MCV.

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

PURPOSE

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

METHODS

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.

RESULTS

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).

CONCLUSION

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.

Do airway inflammation and airway responsiveness markers at the start of apprenticeship predict their evolution during initial training? A longitudinal study among apprentice bakers, pastry makers and hairdressers

Background

The natural history of airway inflammation and symptoms in occupations at risk of asthma is still not fully understood. We aimed to study the evolution during apprenticeship of inflammation markers, bronchial hyperresponsiveness (BHR) and symptoms in at-risk subgroups as defined from measurements of markers made shortly after the start of training.

Methods

Respiratory symptoms, FEV₁ and airway resistance post-bronchial challenge (MBC) test results, fractional exhaled nitric oxide (FeNO) measurements, and eosinophils in nasal lavage fluid were investigated in apprentice bakers, pastry-makers and hairdressers. Four visits were conducted: at the start of the training and every six months thereafter. Four baseline risk groups were defined, based on, (i) a high level of FeNO (NO), (ii) eosinophils > 1% (Eosino), (iii) a ≥ 15% decrease in FEV₁ during the MBC test (HR), and (iv) a ≥ 50% increase in the resistance (Resist). The statistical analysis relied on mixed models.

Results

At baseline, the inflammation markers were related to the MBC markers. There was no evidence to suggest that the baseline risk groups predict a differential evolution of the airway inflammation and bronchial responsiveness markers, or the asthma-like symptoms considered. The baseline risk groups defined from MBC test predicted the levels of MBC markers. Similarly, the baseline risk groups based on eosinophilic inflammation predicted the levels of markers for eosinophilia. These results were similar in the three training tracks, with the exception of the FeNO levels which were not different according to the Eosino risk group. Twelve possible new asthma cases were identified, only the HR risk group predicted their occurrence.

Conclusions

Among this young population, at-risk groups based on initial high levels of inflammation markers did not experience any worsening during the follow-up. However, initial BHR predicted consistently high levels of all markers considered and occurrence of possible asthma.

Electronic supplementary material

The online version of this article (10.1186/s12890-018-0674-9) contains supplementary material, which is available to authorized users.

Male infertility among bakers associated with exposure to high environmental temperature at the workplace

Objective

This study aimed to evaluate the prevalence of male infertility among bakers exposed to high environmental temperature.

Methods

This cross-sectional study was conducted to obtain information using a validated questionnaire administered through an interview. The mean wet bulb globe temperature (WBGT) index in the bakeries was measured. A new statistical formula was used to estimate the prevalence of infertility among bakers.

Results

A total of 137 bakers working in 20 bakeries and 107 individuals included in the comparable control group with variations in age, race, marital status, and income and with history of cigarette smoking were recruited. Using a newly devised formula, the prevalence of infertility among the exposed group was 22.7%, compared with 3.0% in the control group (p = 0.013). All possible confounding factors associated with infertility among bakers were excluded such as cigarette smoking, age, and race. There were unfavorable hot working conditions in bakeries, with a WBGT index of 37.4 °C, while the average WBGT for offices was 25.5 °C (p < 0.0001).

Conclusion

Our study showed that the rate of infertility among bakers was high, which resulted from exposure to high environmental temperature at the workplace as evidenced by the WBGT index. This finding should alert the healthcare authorities to take necessary measures under the labor code to curtail infertility among bakers.

Sensitization to xylanolytic enzymes: an underestimated health hazard among bakers

BACKGROUND

The most important occupational allergens in baking include flour and enzymes, especially α-amylase. Although xylanolytic enzymes have previously been described as sensitizers, they may be overlooked during assessment of bakery workers with work-related symptoms.

AIMS

To report a case of a baker who suffered from work-related respiratory, ocular and skin symptoms as a consequence of sensitization to xylanolytic enzymes.

METHODS

Physical examination, chest X-ray, routine laboratory tests, skin prick tests (SPTs) with common and occupational allergens (wheat, pearl, rye, corn and oat flours, α-amylase, bakery adjuvants) and spirometric measurements, as well as assessments by a laryngologist, dermatologist and ophthalmologist were performed. Specific IgE (sIgE) to occupational agents were evaluated for flours, α-amylase, xylanase, cellulose and glucoamylase. Specific inhalation challenges (SICs) with flours and bakery adjuvants were carried out.

RESULTS

Hypersensitivity to Aspergillus moulds, flours and α-amylase was confirmed in SPTs; however, SIC with those agents gave a negative result. Further investigation revealed the presence of sIgE to xylanolytic enzymes. During SIC with bakery adjuvants, allergic skin, ocular and respiratory symptoms occurred and were confirmed by objective assessment.

CONCLUSIONS

In the assessment of work-related allergic symptoms in bakers, sensitization to xylanolytic enzymes should be considered. Completion of diagnostic procedures having excluded asthma and rhino-conjunctivitis related to flour hypersensitivity might result in a false-negative assessment.

[Dust mites as occupational allergens in two bakeries of La Habana, Cuba]

BACKGROUND

Occupational allergies are becoming more frequent. The allergens present in the working environment of bakeries, such as mites, are not well identified despite being known risk factors of respiratory diseases.

OBJECTIVES

To isolate and identify the species of mites present in two bakeries in La Habana, Cuba, with high sensitization of mites on their workers.

MATERIAL AND METHOD

A descriptive study was done in which samples were taken by tripled from potential sources of mites in bakeries -as flourin use, spills of wheat on the floors, wheat flour stored in sealed bags, sugar, yeast, granulated baker- that were processed, according to the method of flotation of Hart and Fain (1987) to isolate, identify and count the mites present.

RESULTS

Mites were found in samples of wheat flourin use, spills on the floorsand in the wheat flourstored in sealed bags. The species identified were Blomia tropicalis (70%), Tyrophagus putrescentiae (20%) and to a lesser degree Dermatophagoides pteronyssinus and Dermatophagoides siboney.

CONCLUSIONS

There is a high exposure to house dust mites, particularly to store mites, which constitute a risk factor of occupational allergy to consider.