A cross-sectional study of exposures, lung function and respiratory symptoms among aluminium cast-house workers.

UNLABELLED: OBJECTIVES To investigate exposures, respiratory symptoms, lung function and exposure-response relationships among aluminium cast-house workers. METHODS: A cross-sectional study was conducted among 182 workers. Exposure data were used to model exposure to irritants. Lung function and questionnaire data on respiratory symptoms were compared to a general population sample and an internal reference group. Blood samples were taken from 156 workers to examine total IgE, eosinophils and sensitisation to common allergens. RESULTS: Average daily mean exposure to inhalable dust, metals, hydrogen fluoride, fluoride salts and sulphur dioxide was relatively low compared to reference values. Airflow patterns in the hall were disturbed regularly and resulted in pot emissions with high concentrations of fluorides. Peak exposures to chlorine gas occurred intermittently due to production process disturbances. Workers reported significantly more respiratory symptoms (continuous trouble with breathing (prevalence ratio (PR) 2.5; 95% CI 1.2 to 5.3), repeated trouble with breathing (PR 1.8; 95% CI 1.1 to 3.0), wheezing (PR 1.4; 95% CI 1.1 to 1.8), asthma attack (ever) (PR 2.8; 95% CI 1.7 to 4.6) and doctor diagnosed asthma (PR 2.6; 95% CI 1.5 to 4.4). Regression analysis showed significantly lower FEV(1) values (-195 ml) and FVC values (-142 ml) compared to a general population sample. Lung function did not differ between groups. CONCLUSION: This epidemiological study suggests cast-house workers in the aluminium industry are exposed to respiratory hazards. Exposure-response relationships could not be demonstrated but this study supports preventive measures in the work environment with a focus on (peak) exposures to irritants.

Application of a prediction model for work-related sensitisation in bakery workers.

Identification of work-related allergy, particularly work-related asthma, in a (nationwide) medical surveillance programme among bakery workers requires an effective and efficient strategy. Bakers at high risk of having work-related allergy were indentified by use of a questionnaire-based prediction model for work-related sensitisation. The questionnaire was applied among 5,325 participating bakers. Sequential diagnostic investigations were performed only in those with an elevated risk. Performance of the model was evaluated in 674 randomly selected bakers who participated in the medical surveillance programme and the validation study. Clinical investigations were evaluated in the first 73 bakers referred at high risk. Overall 90% of bakers at risk of having asthma could be identified. Individuals at low risk showed 0.3-3.8% work-related respiratory symptoms, medication use or absenteeism. Predicting flour sensitisation by a simple questionnaire and score chart seems more effective at detecting work-related allergy than serology testing followed by clinical investigation in all immunoglobulin E class II-positive individuals. This prediction based stratification procedure appeared effective in detecting work-related allergy among bakers and can accurately be used for periodic examination, especially in small enterprises where delivery of adequate care is difficult. This approach may contribute to cost reduction.

A cross-sectional study among detergent workers exposed to liquid detergent enzymes.

OBJECTIVES: To investigate sensitisation and respiratory health among workers who produce liquid detergent products and handle liquid detergent enzymes. METHODS: We performed a cross-sectional study among 109 eligible workers of a detergent products plant. 108 were interviewed for respiratory and allergic symptoms and 106 blood samples were taken from them to examine sensitisation to enzymes. Those sensitised to > or = 1 enzymes were referred for clinical evaluation. Workers and representatives were interviewed to characterise exposure qualitatively and estimate exposure semi-quantitatively. Workers were classified into three exposure groups with varying exposure profiles to enzymes, based on frequency, duration, and level of exposure. RESULTS: Workers were exposed to proteases, alpha-amylase, lipase and cellulase. The highest exposures occurred in the mixing area. Liquid spills with concentrated enzyme preparations and leakage of enzymes during weighing, transportation and filling were causing workplace contaminations and subsequently leading to both dermal and inhalation exposure for workers. Workers with the highest exposures reported significantly more work-related symptoms of itching nose (prevalence ratio (PR) = 4.2, 95% CI 1.5 to 12.0) and sneezing (PR = 4.0, 95% CI 1.5 to 10.8) and marginally significant more symptoms of wheezing (PR = 2.9, 95% CI 0.9 to 8.7) compared with the least exposed group. Fifteen workers (14.2%) were sensitised to > or = 1 enzymes. A marginally statistically significant gradient in sensitisation across the exposure categories was found (p = 0.09). There was a clinical case of occupational asthma and two others with probable occupational rhinitis. CONCLUSIONS: Workers exposed to liquid detergent enzymes are at risk of developing sensitisation (14%) and respiratory allergy.

A cross-sectional study of lung function and respiratory symptoms among chemical workers producing diacetyl for food flavourings.

OBJECTIVES: Four diacetyl workers were found to have bronchiolitis obliterans syndrome. Exposures, respiratory symptoms, lung function and exposure-response relationships were investigated. METHODS: 175 workers from a plant producing diacetyl between 1960 and 2003 were investigated. Exposure data were used to model diacetyl exposure. Lung function and questionnaire data on respiratory symptoms were compared to a general population sample and respiratory symptoms to an internal reference group. RESULTS: Workers were potentially exposed to acetoin, diacetyl, acetaldehyde and acetic acid. Historic diacetyl exposure ranged from 1.8 to 351 mg/m(3), and from 3 to 396 mg/m(3) for specific tasks. Diacetyl workers reported significantly more respiratory symptoms compared to the general population sample (continuous trouble with breathing (prevalence ratio (PR) = 2.6; 95% CI 1.3 to 5.1), daily cough (PR = 1.5; 95% CI 1.1 to 2.1), asthma attack (ever) (PR = 2.0; 95% CI 1.2 to 3.4), doctor diagnosed asthma (PR = 2.2; 95% CI 1.3 to 3.8) and asthma attack in the last year (PR = 4.7; 95% CI 1.9 to 11.4)) and to a minimally exposed internal reference group (ever trouble with breathing (PR = 2.8; 95% CI 1.1 to 7.0) and work-related shortness of breath in the last year (PR = 7.5; 95% CI 1.1 to 52.9)). Lung function did not differ between groups. A positive relationship between exposure and FEV(1) was found. CONCLUSION: The excess of respiratory symptoms in this retrospective cohort suggests that diacetyl production poses an occupational hazard. Limited historical exposure data did not support a quantitative individual diacetyl exposure-response relationship, but our findings suggest that preventive measures are prudent.

Prevention of work-related airway allergies; summary of the advice from the Health Council of the Netherlands.

The Health Council of the Netherlands published a report in which the best procedure and method for recommending health-based occupational exposure limits (OELs) for inhaled allergens were identified by evaluating the scientific state of the art. Many respiratory disorders in the workplace arise from inhalation of substances which can cause allergy. To protect workers against respiratory allergy, various preventive measures are taken, one of them being reduction of exposure by setting legally binding standards. These are based on health-based OELs that specify a level of exposure to an airborne substance, a threshold level, below which it may reasonably be expected that there is no risk of adverse health effects. The Council is of the opinion that an OEL should prevent against allergic sensitization, as sensitization plays a crucial biological role and is a prerequisite for the development of allergy. Furthermore, the Council considers it most likely that the exposure level below which no allergic sensitization develops for most allergens is so low, that OELs are difficult to set with the current knowledge and technical feasibilities. An alternative approach is to accept exposure, which carries a small predefined risk in developing allergic sensitization. In addition, it is worth considering periodic screening of exposed workers on allergic sensitization, because timely intervention can prevent worse. The feasibility of periodic screening and what else is needed to comply with the most important criteria, should however be judged case-by-case.