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Objectives Recently developed quantitative health impact assessment (HIA) methods provide insight into the impact of interventions on the population burden of disease. This information might subsequently be used in a cost-benefit analysis. In this study we developed a method that allocates costs and benefits across different stakeholders (employer, employees and society) and provides an evidence base for selecting the strategy that maximises the cost-benefit ratio. The developed methodology was applied two intervention strategies focusing on reducing respiratory diseases among Dutch bakery workers; an educational intervention program and a hypothetical strategy that combined health surveillance with individual workplace interventions. Methods A cost-benefit framework describing all cost-elements was developed and used to set up a calculation spreadsheets. This was used to calculate total costs, total benefits, net costs and benefit-to-costs-ratio for both intervention scenarios. Results Implementation of the first intervention program resulted in benefits of €16 848 546 over a 20-year period. For the health surveillance scenario intervention costs could not be calculated. Based upon a total benefit of €44 659 352 and an estimated 4200 individual interventions cost of an individual intervention should stay below 10 000 Euro or below 4650 Euro if the employer covers all costs. Conclusions Our case study highlights the importance of considering the cost and benefit allocation among stakeholders. This is critical from an employer's perspective, as they frequently cover the costs of prevention, but also provides insight into societal benefits like maintaining employee income or reducing strain on government health programs.

OBJECTIVES: Use of cost-benefit analysis in occupational health increases insight into the intervention strategy that maximises the cost-benefit ratio. This study presents a methodological framework identifying the most important elements of a cost-benefit analysis for occupational health settings. One of the main aims of the methodology is to evaluate cost-benefit ratios for different stakeholders (employers, employees and society). The developed methodology was applied to two intervention strategies focused on reducing respiratory diseases. METHODS: A cost-benefit framework was developed and used to set up a calculation spreadsheet containing the inputs and algorithms required to calculate the costs and benefits for all cost elements. Inputs from a large variety of sources were used to calculate total costs, total benefits, net costs and the benefit-to-costs ratio for both intervention scenarios. RESULTS: Implementation of a covenant intervention program resulted in a net benefit of €16?848?546 over 20 years for a population of 10?000 workers. Implementation was cost-effective for all stakeholders. For a health surveillance scenario, total benefits resulting from a decreased disease burden were estimated to be €44?659?352. The costs of the interventions could not be calculated. CONCLUSION: This study provides important insights for developing effective intervention strategies in the field of occupational medicine. Use of a model based approach enables investigation of those parameters most likely to impact on the effectiveness and costs of interventions for work related diseases. Our case study highlights the importance of considering different perspectives (of employers, society and employees) in assessing and sharing the costs and benefits of interventions.

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.

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 >=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 >=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.

Rationale: Workers in microwave popcorn plants are at risk of developing bronchiolitis obliterans associated with exposure to butter flavoring volatiles, including diacetyl. Objectives: To investigate the risk of bronchiolitis obliterans for chemical workers producing diacetyl, with exposure to less complex mixtures of chemicals. Methods: We interviewed and conducted spirometry on 175 of 196 workers from a chemical production plant that produced diacetyl between 1960 and 2003. We used all available historical exposure data to classify all workers into three exposure groups with varying exposure profiles to diacetyl, based on frequency and level of exposure. Measurements and Main Results: Workers with fixed airway obstruction underwent further pulmonary function testing (including diffusing capacity and lung volumes) and paired inspiratory and expiratory high-resolution computed tomography studies. We identified three cases consistent with bronchiolitis obliterans syndrome with air trapping on high-resolution computed tomography of the lungs, in the highest exposure group of 102 process operators. Two of these cases were lifelong nonsmokers. Potential exposures included acetoin, diacetyl, acetaldehyde, and acetic acid, with diacetyl exposures in the range previously reported to be associated with fixed airway obstruction in the microwave popcorn industry. Conclusions: Exposure to an agent during diacetyl production appears to be responsible for causing bronchiolitis obliterans syndrome in chemical process operators, consistent with the suspected role of diacetyl in downstream food production.

In this thesis, results are presented of a cross-sectional epidemiological study among a few hundred bakery workers. Main focus was on the relationship between allergen exposure and the development of specific sensitization and respiratory allergy. Immunoassays were developed for measuring airborne allergens from wheat flour and fungalα-amylase, an enzymatic dough improver. A total of 571 personal inhalable dust samples were available from 230 workers. Wheat flour allergens were measured in 449 of these samples with an inhibition enzyme immuno assay, and an anti-wheat IgG 4 serum pool from bakery workers. Fungalα-amylase allergens were measured in 507 samples in a sandwich immunoassay, using affinity purified polyclonal rabbit IgG 4 antibodies. The validity and specificity of both assays were extensively tested. All bakery workers were categorized into groups, based on their job histories and the wheat orα-amylase allergen exposure levels of their job titles. Optimal grouping strategies were tested. For both orα-amylase and wheat allergens, a clear exposure- sensitization-relationship was found. Atopy appeared to be an important effect modifier of this relationship, and the steepest slope between allergen level and sensitization rate was found within the group of atopic workers. Twenty-three percent of the bakers reported work-related rhinitis or chest-tightness. Symptomatic bakers were divided into occupationally sensitized and non-sensitized workers. In both groups, a relation between allergen exposure and respiratory symptoms was found, but the slope of the relationship was steeper in sensitized bakers than in non-sensitized bakers.