Prevalence and determinants of burnout among South African doctors during the COVID-19 pandemic.

Background: Burnout, resulting from chronic workplace stress that has been unsuccessfully managed, has previously been documented in doctors. The coronavirus disease 2019 (COVID-19) pandemic has increased occupational challenges faced by doctors, potentiating their risk for burnout. Aim: This study aimed to determine the prevalence and determinants of burnout among medical doctors during the COVID-19 pandemic. Setting: Three public sector hospitals in Gqeberha, South Africa. Methods: A cross-sectional study of 260 voluntary participants was conducted. Participants completed self-administered electronic questionnaires. Logistic regression analysis was performed to explore the determinants of burnout. Results: The prevalence of burnout in this study was 78%. Burnout was significantly associated with being a medical intern or community-service medical officer (adjusted odd ratio [AOR] = 6.72, 1.71-26.40), being in the lowest income band (AOR = 10.78, 2.55-45.49), and using alcohol to manage work-related stress (AOR = 3.01, 1.12-8.04). Job-related factors associated with burnout were experiencing high conflict at work (AOR = 5.04, 1.92-13.20) and high role ambiguity and role conflict (AOR = 4.49, 1.98-10.18). Low support at work (AOR = 9.99, 3.66-27.23), medium job satisfaction (AOR = 5.38, 2.65-10.93) and medium support at work (AOR = 3.39, 1.71-6.73) were positively associated with burnout. Participants with medium (AOR = 0.28, 0.10-0.80) and high levels of resilience (AOR = 0.08, 0.03-0.25) were protected against burnout. Coronavirus disease 2019-related factors were not significantly associated with burnout. Conclusion: The burnout prevalence among South African medical doctors at public hospitals during the COVID-19 pandemic was high and strongly associated with job stress factors. Contribution: Given the increased prevalence of burnout among doctors and the strong associations with job stress factors, mitigation of burnout requires targeted organisational interventions.

Occupational risk factors and exposure-response relationships for airway disease among health workers exposed to cleaning agents in tertiary hospitals.

OBJECTIVES: This study investigated occupational risk factors and exposure-response relationships for airway disease among health workers (HWs) exposed to cleaning agents in two tertiary hospitals in South Africa and Tanzania. METHODS: In this cross-sectional study, 697 participants completed questionnaire interviews while 654 underwent fractional exhaled nitric oxide (FeNO) testing. Asthma Symptom Score (ASS) was computed based on the sum of answers to five questions on asthma-related symptoms in the past 12 months. For exposure-response analyses, cleaning agent-related self-reported exposure variables were categorised into three levels (cleaning product not used; use of a cleaning product for up to 99 min per week and use of a cleaning product for ≥100 min per week). RESULTS: Asthma-related outcomes (ASS and FeNO) demonstrated positive associations with medical instrument cleaning agents (orthophthalaldehyde and enzymatic cleaners) and tasks (instruments precleaning and changing sterilisation solutions) as well as patient care activities (disinfection prior to procedures and disinfecting wounds). A particularly pronounced dose-response relationship was observed between work-related ocular-nasal symptoms and medical instrument cleaning agents (orthophthalaldehyde, glutaraldehyde, enzymatic cleaners, alcohols and bleach) (OR range: 2.37-4.56) and tasks (OR range: 2.92-4.44). A strong association was also observed between ASS and use of sprays for fixed surface cleaning (mean ratio 2.81; 95% CI 1.41 to 5.59). CONCLUSIONS: Specific agents for medical instrument disinfection for example, orthophthalaldehyde and enzymatic cleaners, patient care activities and use of sprays are important occupational risk factors for airway disease among HWs.

Prevalence of work-related skin symptoms and associated factors among tertiary hospital workers exposed to cleaning agents in Southern Africa.

INTRODUCTION: Working with cleaning products is associated with occupational contact dermatitis in health workers (HWs), but information on predictors for these outcomes is limited. OBJECTIVES: This study investigated the prevalence of work-related skin symptoms (WRSS) and associated factors in HWs exposed to cleaning agents in two Southern African tertiary hospitals. METHODS: A cross-sectional study of 697 HWs used an interviewer-administered questionnaire and assessed for atopy using Phadiatop. RESULTS: HWs' median age was 42 years, 77.0% were female and 42.5% were atopic. The prevalence of WRSS in the last 12 months was 14.8%, 12.3% had probable contact dermatitis (PCD) and 3.2% had probable contact urticaria (PCU). Technicians (ORadj 3.91) and tasks involving cleaning and disinfection of skin wounds (ORadj 1.98) were associated with WRSS in the past year. Factors associated with PCD included sterilizing instruments, disinfecting skin before procedures and use of wound adhesives. Factors associated with PCU included specimen preparation using formalin, medical instrument sterilization tasks, and skin/wound cleaning and disinfection. Appropriate glove use when performing patients' skin/wound care was protective against WRSS. CONCLUSIONS: Tasks involving cleaning and disinfecting patients' skin and wounds were associated with WRSS in HWs, especially when performed without gloves.

Work-related allergy and asthma associated with cleaning agents in health workers in Southern African tertiary hospitals.

BACKGROUND: Health workers (HWs) are exposed to diverse cleaning agents in large hospitals. This study determined the prevalence of work-related symptoms, allergic sensitization, and lung function abnormalities in HWs of two tertiary hospitals in Southern Africa. METHODS: A cross-sectional study of 699 HWs (South Africa: SAH, n = 346; Tanzania: TAH, n = 353) was conducted. Health outcomes were assessed using a standardized ECRHS questionnaire, immunological tests (specific IgE antibody to common aero-allergens and to occupational allergens: natural rubber latex [NRL]  Hev b5 and Hev b6.02, chlorhexidine, and ortho-phthalaldehyde [OPA]), spirometry [pre-and post- bronchodilator], methacholine challenge, and fractional exhaled nitric oxide (FeNO). RESULTS: A large proportion of participants (78%) were women. Median age was 42 years, with 76% nurses, 12% cleaners, and 5% administrative workers. Current smoking was more common in SAHWs (12%) than TAHWs (1%). The overall prevalence of doctor-diagnosed asthma was 7%. Atopy was present in 43% of HWs, while 4% were sensitized to OPA, 2% to NRL, and 1% to chlorhexidine. Prevalence of work-related ocular-nasal symptoms (16%) was higher than skin (12%) and chest (7%) symptoms. TAHWs had significantly lower mean lung volumes, higher degrees of significant airflow obstruction and impaired lung function. The prevalence of bronchial hyperresponsiveness in SAHWs (14%) was high. Overall, 23% of HWs had abnormal FeNO; 6% having high (>50 ppb) levels. FeNO was positively associated with sensitization to occupational allergens, primarily OPA and NRL. CONCLUSIONS: HWs from both hospitals had similar prevalence of work-related respiratory symptoms. Sensitization to OPA and NRL appears to be contributing to allergic airway inflammation in these HWs.

The association between ambient NO2 and PM2.5 with the respiratory health of school children residing in informal settlements: A prospective cohort study.

BACKGROUND: No previous epidemiological study has investigated the combined association of long-term ambient nitrogen dioxide (NO2) and particulate matter of diameter size-2.5 (PM2.5) exposure with asthma outcomes among schoolchildren in Africa. OBJECTIVES: This study investigated the independent and co-pollutant association of long-term exposures to ambient air pollutants on asthma-associated outcomes in a cohort of schoolchildren in the Western Cape Province of South Africa. METHODS: A total of 590 grade-4 schoolchildren residing in four informal settlements were studied. Spirometry and fractional exhaled nitric-oxide (FeNO) measurements were conducted, including a standardized questionnaire administered to caregivers at baseline and 12-months follow-up. Annual NO2 and PM2.5 levels were estimated for each child's home using land-use regression modelling. Single- and two-pollutant models were constructed to assess the independent and co-pollutant association of both air pollutants (NO2 and PM2.5) on new cases of asthma-associated outcomes adjusting-for host characteristics, indoor exposures and study area. RESULTS: The annual average concentration of PM2.5 and NO2 were 10.01µg/m3 and 16.62µg/m3 respectively, across the four study areas, and were below the local Standards of 20µg/m3 and 40µg/m3, for both pollutants, respectively. In the two-pollutant-adjusted models, an interquartile range (IQR) increase of 14.2µg/m3 in NO2 was associated with an increased risk of new onset of ocular-nasal symptoms (adjusted odds ratio-aOR: 1.63, 95% CI: 1.01-2.60), wheezing (aOR: 3.57, 95% CI: 1.18-10.92), more than two or more asthma symptom score (aOR: 1.71, 95% CI: 1.02-2.86), and airway inflammation defined as FeNO > 35 ppb (aOR: 3.10, 95% CI: 1.10-8.71), independent of PM2.5 exposures. CONCLUSION: This study provided evidence that ambient NO2 levels below local standards and international guidelines, independent of PM2.5 exposure, increases new cases of asthma-associated outcomes after 12-months.

Predictors of discordant latent tuberculosis infection test results amongst South African health care workers.

BACKGROUND: The tuberculin skin test (TST) and interferon-gamma-release-assays (IGRAs) are utilized in screening programmes for presumed latent tuberculosis infection (LTBI) in health care workers (HCWs). However, inter-test comparison yields high rates of discordance, which is poorly understood. The aim of the study was therefore to identify factors associated with discordance amongst HCWs in a TB and HIV endemic setting. METHODS: 505 HCWs were screened for LTBI in South Africa using the TST and two IGRA assays (QuantiFERON-TB-Gold-In-Tube (QFT-GIT) and TSPOT.TB). Factors associated with discordance were analyzed using a multinomial logistic regression model. RESULTS: TST-IGRA discordance was negatively associated with longer duration of employment for both TSPOT.TB (OR = 0.92; 95% confidence interval (CI) 0.85-0.99) and QFT-GIT (OR = 0.90; 95% CI 0.84-0.96). Marked test discordance occurred in HIV-infected individuals who were more likely to have TSPOT.TB + ve / TST-ve discordance (OR 4.44; 95% CI 1.14-17.27) or TSPOT.TB + ve / QFT-GIT-ve test discordance (OR 5.72; 95% CI 1.95-16.78). Those engaged in home care were less likely to have QFT-GIT + ve/TSPOT.TB -ve / discordance (OR 0.32; 95% CI 0.10-0.95). CONCLUSION: The marked TST-IGRA and IGRA-IGRA discordance in HIV-infected individuals suggest greater sensitivity of TSPOT.TB in immunocompromised persons or potential greater reactivity of TSPOT.TB in this population.

Risk factors associated with allergic sensitization and asthma phenotypes among poultry farm workers.

BACKGROUND: This study investigated the risk factors for occupational allergic sensitization and various asthma phenotypes in poultry-workers. METHODS: A cross-sectional study of 230 workers used a modified ECRHS questionnaire, spirometry, FeNO, Phadiatop, and sIgE to poultry farming related allergens. RESULTS: Worker's mean age was 37 ± 9 years, 68% male, 43% current-smokers, 34% atopic, and 5% casual-workers. The prevalence of non-atopic asthma (NAA = 7%) was higher than atopic-asthma (AA = 5%) and probable allergic occupational-asthma (OA = 3%). Sensitization to at least one poultry farming related allergen was 24%. Workers sensitized to chicken-specific-allergens were more likely to be atopic (ORunadj = 20.9, 95%CI: 4.7-93.2) or employed as casual-workers (ORunadj = 6.0, 95%CI: 1.1-35.9). Work-related chest symptoms were associated the rearing-department (ORadj = 3.2, 95%CI: 1.2-8.4) and exposure to high gas/dust/fumes (ORadj = 4.8, 95%CI: 2.4-9.5). Airflow reversibility (ORadj = 10.9, 95%CI: 2.0-60.3) was significantly associated with casual-work status. CONCLUSION: Allergic and non-allergic mechanisms play a role in asthma development among poultry-workers with casual workers demonstrating increased risk.

A prospective cohort study on ambient air pollution and respiratory morbidities including childhood asthma in adolescents from the western Cape Province: study protocol.

BACKGROUND: There is evidence from existing literature that ambient air pollutant exposure in early childhood likely plays an important role in asthma exacerbation and other respiratory symptoms, with greater effect among asthmatic children. However, there is inconclusive evidence on the role of ambient air pollutant exposures in relation to increasing asthma prevalence as well as asthma induction in children. At the population level, little is known about the potential synergistic effects between pollen allergens and air pollutants since this type of association poses challenges in uncontrolled real life settings. In particular, data from sub-Sahara Africa is scarce and virtually absent among populations residing in informal residential settlements. METHODS/DESIGN: A prospective cohort study of 600 school children residing in four informal settlement areas with varying potential ambient air pollutant exposure levels in the Western Cape in South Africa is carried-out. The study has two follow-up periods of at least six-months apart including an embedded panel study in summer and winter. The exposure assessment component models temporal and spatial variability of air quality in the four study areas over the study duration using land-use regression modelling (LUR). Additionally, daily pollen levels (mould spores, tree, grass and weed pollen) in the study areas are recorded. In the panel study asthma symptoms and serial peak flow measurements is recorded three times daily to determine short-term serial airway changes in relation to varying ambient air quality and pollen over 10-days during winter and summer. The health outcome component of the cohort study include; the presence of asthma using a standardised ISAAC questionnaire, spirometry, fractional exhaled nitric-oxide (FeNO) and the presence of atopy (Phadiatop). DISCUSSION: This research applies state of the art exposure assessment approaches to characterize the effects of ambient air pollutants on childhood respiratory health, with a specific focus on asthma and markers of airway inflammation (FeNO) in South African informal settlement areas by considering also pollen counts and meteorological factors. The study will generate crucial data on air pollution and asthma in low income settings in sub-Sahara Africa that is lacking in the international literature.

Environmental factors associated with baseline and serial changes in fractional exhaled nitric oxide (FeNO) in spice mill workers.

BACKGROUND: This study evaluated the determinants of high fractional exhaled nitric oxide (FeNO; >50 ppb) and serial changes in FeNO over a 24-hour period in spice mill workers at risk of work-related allergic respiratory disease and asthma. METHODS: A cross-sectional study of 150 workers used European Community Respiratory Health Survey (ECRHS) questionnaires, Phadiatop, serum-specific IgE (garlic, chilli pepper, wheat; Phadia, ImmunoCAP), spirometry and FeNO. A hand-held portable nitric oxide sampling device (NIOX MINO, Aerocrine AB) measured FeNO before and after the 8-hour shift and after 24 hours from baseline. RESULTS: The mean age of workers was 33 years; 71% were male, 46% current smokers and 45% atopic. Among workers with garlic sensitisation, 13% were monosensitised and 6% were co-sensitised to chilli pepper. Baseline preshift FeNO geometric mean (GM=14.9 ppb) was similar to the mean change across shift (GM=15.4 ppb) and across the 24-hour period (GM=15.8 ppb). In multivariate linear models, smoking (ß=-0.507) and atopy (ß=0.433) were strongly associated with FeNO. High FeNO (>50 ppb) was significantly associated with asthma-like symptoms due to spice dust (OR=5.38, CI 1.01 to 28.95). Sensitisation to chilli pepper was more strongly correlated with FeNO (r=0.32) and FeNO>50 ppb (OR=17.04, p=0.005) than garlic. FeNO increase (>12%) across 24 hours demonstrated a strong association with elevated exposures to spice dust particulate (OR=3.77, CI 1.01 to 14.24). CONCLUSIONS: This study suggests that chilli pepper sensitisation is associated with high FeNO (>50 ppb), more strongly compared with garlic, despite the low prevalence of sensitisation to chilli. Elevated inhalant spice dust particulate is associated with a delayed elevation of FeNO across the 24-hour period.

Incidence of occupational latent tuberculosis infection in South African healthcare workers.

The test-specific incidence of latent tuberculosis infection (LTBI) in healthcare workers from sub-Saharan Africa is unknown. 505 healthcare workers from South Africa were screened at baseline, and after 12 months, with a questionnaire, the tuberculin skin test (TST), and two T-cell assays (T-SPOT.TB and QuantiFERON-TB Gold-In-Tube). Test-specific conversion rates were calculated. The prevalence of presumed LTBI at baseline was 84, 69 and 62% using the TST, QuantiFERON-TB Gold-In-Tube and T-SPOT.TB, respectively. The annual test-specific conversion rate, depending on the cut-off point used, was as follows: TST 38%; QuantiFERON-TB Gold-In-Tube 13-22%; and T-SPOT.TB 18-22%. Annual reversion rates were 4, 7 and 16%, respectively. The annual TST conversion rate was significantly higher than that derived from published local community-based data (IRR 3.53, 95% CI 1.81-6.88). Factors associated with conversion (any test) included healthcare sector of employment, counselling of tuberculosis patients, and a baseline positive TST (for T-SPOT.TB). The annual rate of tuberculosis infection in South African healthcare workers was very high, irrespective of the testing method used, and may be explained by occupational exposure, as the rate was considerably higher than non-healthcare workers from the same community. Collectively, these data support the need for implementation of tuberculosis-specific infection control measures in Africa.

Effectiveness of interventions to reduce flour dust exposures in supermarket bakeries in South Africa.

RATIONALE: A recent study of supermarket bakery workers in South Africa demonstrated that 25% of workers were sensitised to flour allergens and 13% had baker's asthma. Evidence on exposure reduction strategies using specifically designed interventions aimed at reducing the risk of baker's asthma is scarce. OBJECTIVES: The aim of this study was to evaluate the effectiveness of different control measures to reduce airborne flour dust exposure using a randomised design. METHODS: A group-randomised study design was used to assign 30 bakeries of a large supermarket chain store to two intervention groups and a control group, of which 15 bakeries were studied. Full-shift environmental personal samples were used to characterise exposure to flour dust and wheat and rye allergens levels pre-intervention (n=176) and post-intervention (n=208). RESULTS: The overall intervention effect revealed a 50% decrease in mean flour dust, wheat and rye allergen exposure. The reduction in exposure was highest for managers (67%) and bakers (47%), and lowest for counterhands (23%). For bakers, the greatest reduction in flour dust was associated with control measures such as the use of the mixer lid (67%), divider oil (63%) or focused training (54%). However, the greatest reduction (80%) was observed when using a combination of all control measures. CONCLUSIONS: A specially designed intervention strategy reduced both flour dust and allergen levels. Best results were observed when combining both engineering controls and training. Further studies will investigate the long-term health impact of these interventions on reducing the disease burden among this group of bakers.

Sensitisation to cereal flour allergens is a major determinant of elevated exhaled nitric oxide in bakers.

OBJECTIVE: Various studies of the usefulness of fractional exhaled nitric oxide (FeNO) in occupational settings remain inconclusive. The objective was to investigate the determinants of increased FeNO in bakery workers. METHODS: A cross-sectional study of 424 supermarket bakery workers used a questionnaire and serum specific IgE to wheat, rye and α-amylase. FeNO during the work shift were assessed using a hand-held portable sampling device (NIOX MINO). RESULTS: The median FeNO was 15 ppb, in atopics 21 ppb and current smokers 12 ppb. Increased FeNO was strongly associated with IgE to wheat independent of smoking and atopy status. In the multivariate model, IgE to wheat, current smoking, atopy and age were significantly associated with FeNO. Stratified analysis in a subgroup of atopic non-smokers demonstrated the strongest relationship between FeNO and various clinical endpoint such as wheat (OR=9.43) or rye (OR=11.76) sensitisation, work-related allergic rhinitis (OR=8.13) or asthma (OR=5.44), and probable baker's asthma (OR=6.72). CONCLUSIONS: Sensitisation to cereal flour allergens rather than asthma symptoms is a major determinant of elevated FeNO among bakers. This relationship is modified by atopy and current smoking status.

Work-related allergic respiratory disease and asthma in spice mill workers is associated with inhalant chili pepper and garlic exposures.

OBJECTIVE: The aim of the study was to determine the prevalence and risk factors for allergic respiratory disease in spice mill workers. METHODS: A cross-sectional study of 150 workers used European Community Respiratory Health Survey questionnaires, Phadiatop, serum specific IgE (garlic, chili pepper), spirometry and fractional exhaled nitric oxide (FeNO). Personal air samples (n=62) collected from eight-hour shifts were analysed for inhalable particulate mass. Novel immunological assays quantified airborne garlic and chili pepper allergen concentrations. RESULTS: Mean dust particulate mass (geometric mean (GM)=2.06 mg/m(3)), chili pepper (GM=0.44 µg/m(3)) and garlic allergen (GM=0.24 µg/m(3)) were highest in blending and were highly correlated. Workers' mean age was 33 years, 71% were men, 46% current smokers and 45% atopic. Spice-dust-related asthma-like symptoms (17%) were common, as was garlic sensitisation (19%), with 13% being monosensitised and 6% cosensitised to chili pepper. Airflow reversibility and FeNO>50 ppb was present in 4% and 8% of workers respectively. Spice-dust-related ocular-nasal (OR 2.40, CI 1.09 to 5.27) and asthma-like (OR 4.15, CI 1.09 to 15.72) symptoms were strongly associated with airborne garlic in the highly exposed (>0.235 µg/m(3)) workers. Workers monosensitised to garlic were more likely to be exposed to higher airborne chili pepper (>0.92 µg/m(3)) (OR 11.52, CI 1.17 to 113.11) than garlic allergens (OR 5.08, CI 1.17 to 22.08) in this mill. Probable asthma was also more strongly associated with chili pepper than with garlic sensitisation. CONCLUSIONS: Exposure to inhalable spice dust (GM >2.06 mg/m(3)) containing garlic (GM>0.24 µg/m³) and chili pepper (GM >0.44 µg/m(3)) allergens increase the risk of allergic respiratory disease and asthma.

Wood dust and asthma.

PURPOSE OF THE REVIEW: Review recent developments on asthma associated with wood dust, given the increasing scale of wood handling and processing activities globally. RECENT FINDINGS: Work in wood industries is associated with a significantly increased risk of respiratory symptoms, rhinitis and asthma. This can be attributed to traditional processing techniques and newer technologies producing complex bioaerosol exposures, which may include chemicals. Meta-analysis studies indicate strong evidence for wood dusts as occupational sensitizers for asthma, but the underlying mechanisms remain poorly understood. The global prevalence of asthma in wood workers ranges between 6-18% and for rhinitis 16-33%. Exposure estimates show wide variation. Risk factors include atopy and exposure to certain wood species, elevated current and cumulative particulate exposures. SUMMARY: Future studies should focus on better characterization of wood dust allergens and other bioaerosol components, specific immunoglobulin E responses to different wood species, pathophysiological mechanisms underlying asthma, and modelling dose-response relationships using refined exposure metrics for dust particulate and other bioaerosol components. There is a need for improved health-based international exposure standards and effective workplace control measures to reduce exposures to wood dust particulate (hard and soft woods), endotoxin and ß-glucan, to reduce the risks of asthma in wood workers.

Obstructive Lung Disease Linked to Occupational Exposures in Malawian Tobacco Farmers.

Nicotine and pesticide exposure in agricultural settings have been linked to the development of chronic respiratory disease in workers. However, this has not been extensively studied in Africa. The aim of this study was therefore to determine the prevalence of obstructive lung disease and its relationship to concurrent nicotine and pesticide exposure among small-scale tobacco farmers in Malawi. For this purpose, sociodemographic characteristics, occupational and environmental exposures were evaluated in relation to work-related respiratory symptoms and lung function impairment. A cross-sectional study was conducted enrolling 279 workers in flue-cured tobacco farms in Zomba, Malawi. The study instruments used for assessing the health outcomes were a standardised European Community Respiratory Health Survey II (ECRHS) questionnaire and Spirometry testing. The questionnaires were aimed at collecting relevant data on sociodemographic factors and self-reported respiratory health outcomes. Data were also collected on potential pesticide and nicotine exposures. Spirometry was done to evaluate objective respiratory impairment in accordance with American Thoracic Society guidelines. The mean age of participants was 38 years with 68% being male. The prevalence of work-related ocular nasal symptoms, chronic bronchitis, and work-related chest symptoms was 20%, 17%, and 29%, respectively. Airflow limitation (FEV1/FVC <70%) was found in 8% of workers. Self-reported exposure to pesticides varied from 72%- to 83%, whilst the prevalence of recent green tobacco sickness was 26%. Tasks linked to nicotine exposure, such as sowing (OR: 2.5; CI 1.1-5.7) and harvesting (OR: 2.6; CI 1.4-5.1), were significantly associated with work-related chest symptoms. Pesticide application (OR:1.96; CI 1.0-3.7) was associated with an increased risk of work-related oculonasal symptoms. Duration of pesticide exposure was also associated with obstructive impairment FEV1/FVC

Occupational Bioaerosol Exposures Associated with Poultry Farming.

This study aimed to investigate occupational exposure to particulate dust, endotoxin, and (1-3)-ß-D-glucan among workers involved in various poultry farming activities. A total of 298 personal samples were collected from randomly selected individuals from exposure groups based on distinct poultry farming activities comprising broiler farms, rearing, laying, hatchery, and catching activities. Aside from the inhalable particulate dust concentration that was determined, filter extracts were also analyzed for (1-3)-ß-D-glucan and endotoxin using the endpoint Glucatell® and Limulus amoebocyte lysate (LAL) assays, respectively. Data were analyzed using STATA 12 and linear regression models developed. The mean (GM) dust particulate concentration was 11.04 mg/m3 (GSD = 3.87); 2298 endotoxin units (EU/m3) (GSD = 10.56) and 149 ng/m3 for (1-3)-ß-D-glucan (GSD = 4.62). A modest positive correlation was observed between log-transformed endotoxin and (1-3)-ß-D-glucan concentrations (Pearson r = 0.44, p < .001), whilst a moderate negative correlation was observed for inhalable dust particulate and (1-3)-ß-D-glucan (Pearson r = -0.33, p < .001). However, there was a very poor correlation between inhalable dust and endotoxin (Pearson r = -0.02, p < .001). In the regression models, exposure group based on the nature of farming activity explained 50% of the variability in dust particulate and glucan levels. For dust particulate, rearing activities were significant predictors of higher dust levels compared to hatchery work, while rearing, laying, broiler and catching activities were significant predictors of higher endotoxin or glucan levels. Furthermore, working in a small broiler was a significant determinant of elevated glucan exposures. Farms using automated laying activities had significantly higher particulate levels compared to those using manual laying activities. This study revealed that workers engaged in poultry farming activities were exposed to significantly high levels of inhalable particulate dust, endotoxin, and (1-3)-ß-D-glucan concentrations, posing an increased risk for adverse respiratory health effects in these farm workers.

Exposure Characterization of Wood Dust Particulate, Endotoxins, and (1-3)-ß-d-Glucans, and Their Determinants in Mozambiquan Wood Processing Workers.

OBJECTIVES: Dust generated from wood processing comprises a heterogeneous mixture of inorganic and organic particles, including wood fragments, microorganisms, endotoxins, (1-3)-ß-d-glucans, and allergens. This study characterized exposure to wood dust and its determinants in the Mozambiquan wood processing industry. METHODS: A total of 124 personal inhalable samples, collected from a stratified random sample of 30 workers, were analysed for dust particulate, endotoxins, and (1-3)-ß-d-glucans. Mixed-effects models were developed to investigate significant exposure determinants. RESULTS: The geometric mean (GM) inhalable dust particulate concentrations were 3.29 mg m-3, 98 endotoxin units (EU) m-3, and 123 ng m-3 for (1-3)-ß-d-glucans. Significant predictors for higher particulate levels included machinery (GMR = 1.93), sawing (GMR = 2.80), carpentry (GMR = 2.77), or painting (GMR = 3.03) tasks. Lebombo-ironwood species was associated with higher dust particulate levels (GMR = 1.97). Determinants of endotoxin concentrations included working with dry wood and damp cleaning methods, which were associated with lower levels. Working in closed buildings (GMR = 3.10) and dry sweeping methods were associated with higher (1-3)-ß-d-glucan concentrations (GMR = 1.99). CONCLUSIONS: Work tasks in certain exposure groups (machinery, sawing, carpentry, painting), processing certain wood species (Lebombo-ironwood) and working in closed buildings were associated with higher exposures, whilst using dry wood and damp cleaning practices reduced exposure levels.

Occupational inhalant allergy in food handling occupations.

PURPOSE OF REVIEW: Review article on recent developments on inhalant food allergens associated with occupational respiratory allergy and asthma. RECENT FINDINGS: This review has found that occupational inhalant allergy in food handling occupations is a common and recognisable clinical entity (class 3 food allergy) in high-risk food occupations such as bakeries and seafood processing. Aerosolised food proteins from plant or animal food sources, additives and biological food contaminants cause occupational sensitization, rhinitis and asthma. The risk of allergy may be enhanced across the food value chain as a result of food processing techniques including the introduction of new food allergens in the food matrix. Occupational food allergy and asthma can be prevented by improved health-based exposure standards, workplace control measures, education and training activities, and early diagnosis accompanied with exposure reduction. SUMMARY: Future studies need to focus on exposure-response studies to establish improved exposure limits especially for flour dust, the relevance of cooked vs raw foods in influencing risk, identifying and characterising major inhalant food allergens accompanied with component resolved diagnostic approaches, and evaluating the effectiveness of interventions for common high-risk food sensitizers causing occupational rhinitis and asthma.

Health-Related Quality of Life (HRQoL) of Residents with Persistent Lower Respiratory Symptoms or Asthma Following a Sulphur Stockpile Fire Incident.

Background: This study evaluated health-related quality of life (HRQoL) in residents with persistent lower respiratory symptoms (PLRS) or asthma six years after exposure to sulphur dioxide vapours emanating from an ignited sulphur stockpile. Methods: A cross-sectional study was carried out, using interview data collected at three time points (prior to, one- and six-years post incident), medical history, respiratory symptoms and HRQOL using the Medical Outcomes Study Form 36 (SF-36). Results: A total of 246 records, 74 with and 172 without PLRS or asthma, were analysed. The mean age was 42 (SD:12) years in the symptomatic group and 41 (SD:13) years in the asymptomatic group. Mean SF-36 scores were significantly lower for the symptomatic group in the Physical Functioning (24 vs. 39), Role-Physical (33 vs. 48) and General Health (GH) domains (24 vs. 37). Symptomatic residents experienced a significant decline in their Role-Physical (OR = 1.97; CI 1.09, 3.55) and GH (OR = 3.50; CI 1.39, 8.79) at year 6 compared to asymptomatic participants. Residents with co-morbid reactive upper airways dysfunction syndrome demonstrated stronger associations for GH (OR = 7.04; CI 1.61, 30.7) at year 1 and at year 6 (OR = 8.58; CI 1.10, 65.02). Conclusions: This study highlights the long-term adverse impact on HRQoL among residents with PLRS or asthma following a sulphur stockpile fire disaster.

Asthma Phenotypes and Host Risk Factors Associated With Various Asthma-Related Outcomes in Health Workers.

Background: Work-related asthma phenotypes in health workers (HWs) exposed to cleaning agents have not been investigated extensively as other occupational exposures. This study aimed to describe asthma phenotypes and to identify important host risk factors associated with various asthma-related outcomes. Methods: A cross-sectional study of 699 HWs was conducted in two large tertiary hospitals. A total of 697 HWs completed questionnaire interviews. Sera collected from 682 HWs were analyzed for atopy (Phadiatop) and IgE to occupational allergens (NRL-Hev b5, Hev b6.02; chlorhexidine and ortho-phthalaldehyde-OPA). Methacholine (MCT), bronchodilator challenge (BDR) and fractional exhaled nitric oxide (FeNO) were performed. An asthma symptom score (ASS) used five asthma-related symptoms reported in the past 12 months. Current asthma was based on use of asthma medication or an asthma attack or being woken up by an attack of shortness of breath in the past 12 months. Nonspecific bronchial hyperresponsiveness (NSBH) was defined as having either a positive MCT or a significant bronchodilator response. Two continuous indices of NSBH [continuous index of responsiveness (CIR) and dose-response slope (DRS)] were calculated. Results: The prevalence of current asthma was 10%, atopic asthma (6%) and non-atopic asthma (4%). Overall, 2% of subjects had work-related asthma. There was a weak positive association between NSBH and FeNO [CIR: Beta coefficient (ß) = 0.12; CI: 0.03-0.22 and DRS: ß = 0.07; CI: 0.03-0.12]. Combining FeNO ≥ 50 ppb with a BDR [mean ratio (MR) = 5.89; CI: 1.02-34.14] or with NSBH (MR = 4.62; CI: 1.16-18.46) correlated better with ASS than FeNO alone (MR = 2.23; CI: 1.30-3.85). HWs with current asthma were twice as likely to be atopic. FeNO was positively associated with atopy (OR = 3.19; CI: 1.59-6.39) but negatively associated with smoking status (GMR = 0.76; CI: 0.62-0.94). Most HWs sensitized to occupational allergens were atopic. Conclusion: Atopic asthma was more prevalent than non-atopic asthma in HWs. Most asthma-related outcomes were positively associated with allergic predictors suggesting a dominant role for IgE mechanisms for work-related symptoms and asthma associated with sensitization to OPA or chlorhexidine.