Príručka ku genealogickému výskumu na Slovensku a v slovacikálnom zahraniči

Рецензія на збірник: Príručka ku genealogickému výskumu na Slovensku a v slovacikálnom zahraniči / Zostavil a zredigoval Milan Šišmiš. – Zväzok 2. – Martin: Slovenská genealogicko-heraldická spoločnosť, 2009. – 270 s. ISBN 978-80-970196-1-7

Exposure intervention and health impact assessment : The example of baker's asthma

The regular occurrence of respiratory allergies associated with occupational exposure to flour dust and other allergens, initiated a covenant supported by major flour processing sectors (bakeries, flour mills and ingredient producers) and social partners. The main goal was to decrease occupational exposures and associated disease burden. Exposure surveys were performed to assess exposure levels to flour dust and allergens and enable evaluation of the impact of the covenant actions. A health surveillance program was initiated to monitor the health status of the working population and intervene when an individual was likely to have a respiratory allergy. To evaluate the impact of potential exposure reductions on the population’s health, an assessment methodology was needed. Consequently, a quantitative health impact assessment methodology was developed. The dynamic population-based model was used to assess the impact of different intervention strategies on the disease burden of work related respiratory symptoms in Dutch bakery workers. The dynamic population-based model was developed using information from the exposure surveys and epidemiological studies performed during the covenant. The model simulates a population of individual workers longitudinally and tracks the development of work-related sensitisation, respiratory symptoms and work disability in each worker. Each worker’s disease state is modelled independently using a discrete time Markov Chain, updated yearly using each individual’s simulated exposure. The model provides a valuable population level representation of the mechanisms contributing to respiratory diseases in bakers, and can be used for quantitative health impact assessment. This is demonstrated through the evaluation of the impact of different intervention strategies on the disease burden of the population over time. Different interventions based on 1) exposure reductions for wheat and fungal alpha-amylase allergens 2) health surveillance combined with individual reduction of exposure for high risk workers and 3) pre-employment screening, were evaluated. The impact of the interventions was compared with the baseline intervention program performed as part of the covenant. The predicted impact of the covenant was modest with a change in the prevalence of the different disease states of less then -15% after 20 years. The impact of most of the other intervention strategies evaluated was higher, but generally less then -50% for lower respiratory symptoms and work disabling asthma. Only the rigorous health surveillance intervention scenario, in which workers are identified who are sensitized or report upper respiratory symptoms and for whom the exposure is decreased by 90%, resulted in a predicted decrease of almost 60% in disease burden after 20 years. These results give an indication of the most effective intervention strategy for decreasing the occupational respiratory disease burden in bakery workers. It also provides more generic lessons for intervention research. This information can assist policy makers in their choice of intervention strategy and gives an indication of achievable reductions in disease burden over time. The different studies in this thesis illustrate the importance and complexity of creating a good quantitative evidence base for occupational intervention. In many occasions, like in many of the Dutch covenants, the evidence base for effective interventions remains weak and can be optimized using quantitative health impact assessment methods

Effect of an intervention aimed at reducing the risk of allergic respiratory disease in bakers: change in flour dust and fungal alpha-amylase levels.

INTRODUCTION: We evaluated the effect on exposure of an intervention programme, which focused on risk education and providing information on good work practices. This intervention programme was enrolled as part of a Dutch covenant in the flour processing industry (industrial bakeries, flour mills, ingredient producers). METHODS: Data from several measurement surveys collected pre- and post-intervention were used to evaluate changes in exposure over time. All datasets contained personal measurements analysed for flour dust and fungal alpha-amylase contents, and contextual information was available on process characteristics, work practice, and use of control measures. RESULTS: Changes in exposure over time varied substantially between sectors and jobs. For bakeries a modest downward annual trend of -2% was found for flour dust and -8% for amylase. For flour mills the annual trend for flour dust was -12%; no significant trend was observed for amylase. For ingredient producers results were generally non-significant but indicated a reduction in flour dust exposure and increase in fungal alpha-amylase exposure. Modest increase in use of control measures and proper work practices were reported in most sectors, especially the use of local exhaust ventilation and decreased use of compressed air. CONCLUSIONS: The magnitude of the observed reductions in exposure levels indicates that the sector-wide intervention strategy implemented during the covenant period had a limited overall effect. This indicates that a more rigorous approach is needed to substantially decrease the exposure levels to flour dust and related allergens and, respectively, the prevalence of associated occupational diseases

Inhalable beta(1->3)glucans as a non-allergenic exposure factor in Dutch bakeries.

OBJECTIVES: To obtain an overview of inhalable beta(1-->3)glucans levels in Dutch industrial bakeries and explore possible associations with reported respiratory health effects in bakery workers. METHODS: beta(1-->3)glucan levels were analysed in 186 personal inhalable dust measurements obtained from a random population of bakery workers. Association between respiratory health effects and exposure to beta(1-->3)glucan was explored in a population of industrial bakery workers participating in a Health Surveillance System for flour processing sectors. Based on their job, bakery workers were assigned to low or high exposure categories given the average job exposure estimates obtained from the measurement study. RESULTS: Bread bakers and dough makers had the highest exposures to beta(1-->3)glucans (GM 1.48 mug/m3 and 1.37 mug/m3 respectively). Strong correlations were found between airborne levels of inhalable dust and beta(1-->3)glucans, and between beta(1-->3)glucans and wheat allergens (Pearson correlation coefficients were 0.74 and 0.68 respectively). No significant associations could be identified between beta(1-->3)glucan exposure and work-related respiratory symptoms. CONCLUSION: This study has shown that bakery workers are exposed to inhalable beta(1-->3)glucan levels comparable with exposure levels found in other occupational settings. More refined exposure assessment is necessary to fully understand the role of beta(1-->3)glucan exposure on respiratory health in bakery workers

Application of a dynamic population-based model for evaluation of exposure reduction strategies in the baking industry

Recently a dynamic population model was developed that simulates a population of bakery workers longitudinally through time and tracks the development of work-related sensitisation and respiratory symptoms in each worker. Input for this model comes from cross-sectional and longitudinal epidemiological studies which allowed estimation of exposure response relationships and disease transition probabilities This model allows us to study the development of diseases and transitions between disease states over time in relation to determinants of disease including flour dust and/or allergen exposure. Furthermore it enables more realistic modelling of the health impact of different intervention strategies at the workplace (e.g. changes in exposure may take several years to impact on ill-health and often occur as a gradual trend). A large dataset of individual full-shift exposure measurements and real-time exposure measurements were used to obtain detailed insight into the effectiveness of control measures and other determinants of exposure. Given this information a population wide reduction of the median exposure with 50% was evaluated in this paper. © 2009 IOP Publishing Ltd

A dynamic population-based model for the development of work-related respiratory health effects among bakery workers.

OBJECTIVES: This paper presents a dynamic population-based model for the development of sensitisation and respiratory symptoms in bakery workers. The model simulates a population of individual workers longitudinally and tracks the development of work-related sensitisation and respiratory symptoms in each worker. METHODS: The model has three components: a multi-stage disease model describing the development of sensitisation and respiratory symptoms in each worker over time; an exposure model describing occupational exposure to flour dust and allergens; and a basic population model describing the length of a worker's career in the bakery sector and the influx of new workers. Each worker's disease state is modelled independently using a discrete time Markov Chain, updated yearly using each individual's simulated exposure. A Bayesian analysis of data from a recent epidemiological study provided estimates of the yearly transition probabilities between disease states. RESULTS: For non-atopic/non-sensitised workers the estimated probabilities of developing moderate (upper respiratory) symptoms and progression to severe (lower respiratory) symptoms are 0.4% (95% CI 0.3 to 0.5%) and 1.1% (95% CI 0.6 to 1.9%) per mg/m(3)/year of flour dust, respectively, and approximately twice these for atopic workers. The model predicts that 36% (95% CI 26 to 46%) of workers with severe symptoms are sensitised to wheat and 22% (95% CI 12 to 37%) to alpha-amylase. The predicted mean latency period for respiratory symptoms was 10.3 years (95% CI 8.3 to 12.3). CONCLUSIONS: While the model provides a valuable population-level representation of the mechanisms contributing to respiratory diseases in bakers, it was primarily developed for use in quantitative health impact assessment. Future research will use the model to evaluate a range of workplace interventions, including achievable reductions in exposure and health surveillance. The general methodology is applicable to other diseases such as chronic obstructive pulmonary disease, silicosis and musculoskeletal disorders and could be particularly valuable for forecasting changes in long latency diseases

What is the best strategy to reduce the burden of occupational asthma and allergy in bakers?

RATIONALE Insight into the effectiveness of intervention strategies will help realise a decrease in the occupational disease burden from (allergic) respiratory diseases in the bakery population. OBJECTIVES To use a simulation model to assess the impact of different intervention strategies on the disease burden of the bakery population over time. METHODS A recently developed dynamic population based model was used to prospectively evaluate the impact on disease burden resulting from different intervention strategies. We distinguished interventions based on exposure reductions for flour dust and fungal α-amylase, health surveillance combined with reduction in exposure, and pre-employment screening. MAIN RESULTS The impact of most interventions on disease burden was limited, generally less than 50% for lower respiratory symptoms and disabling occupational asthma. Only the rigorous health surveillance strategy, identifying workers who are sensitised or report upper respiratory symptoms and decreasing their individual exposures by 90% shortly after diagnosis, resulted in a decrease of almost 60% in disease burden after 20 years. CONCLUSIONS This study demonstrates that different intervention strategies have substantially different impacts on the burden of disease. The time window during which changes occur differs considerably between strategies. This information can assist policy makers in their choice of intervention and gives guidance for achievable reductions in disease burden

Evaluation of peak exposures in the Dutch flour processing industry: Implications for intervention strategies

Objectives: To effectively decrease occupational exposure to flour dust and related allergens, detailed information on exposure determinants and effectiveness of control measures is essential. In this paper, we use personal real-time exposure measurements to get more insight into the relationship between specific work characteristics, including the use of control measures, and (peak) exposure to flour dust. The study has three objectives: (i) identify tasks and activities related to peak exposure, (ii) identify control measures and other important exposure determinants and (iii) assess the potential impact of these control measures on the (peak) exposure to flour dust. Methods: A data set containing 82 real-time exposure measurements in combination with information from detailed observations was used to study the association between peak exposures and different tasks, activities and other determinants such as control measures. Descriptive statistics of peak exposure on job level were generated as well as information on contribution of task-specific peak exposures to time-weighted average (TWA) exposure levels. Finally, we evaluated the efficacy of a variety of control measures on task exposure by comparing exposure levels of groups of workers with and without controls. Results: In workers included in this study, >75% of TWA exposure is directly associated with peak exposures during a limited set of well-defined tasks/activities. The impact of a single task on population TWA exposure is generally limited (<40%). Worker behavior seems an important determinant in effective exposure control for many tasks. Conclusions: Data from real-time measurements provide important detailed information with respect to exposure determinants and control measures, not obtainable from conventional measurement studies focusing at TWA exposure. This information is essential to perform prospective impact assessments of intervention strategies on the populations' exposure distribution. © The Author 2008. Published by Oxford University Press on behalf of the British Occupational Hygiene Society