Work-related asthma.

Work-related asthma (WRA) is highly prevalent in the adult population. WRA includes occupational asthma (OA), which is asthma caused by workplace exposures, and work-exacerbated asthma (WEA), also known as work-aggravated asthma, which is preexisting or concurrent asthma worsened by workplace conditions. In adults, the estimated prevalence of OA is 16.0%, whereas that of WEA is 21.5%. An increasing number of chemicals used in industrial production, households, and services are associated with the incidence of adult-onset asthma attributable to exposure to chemicals. This review article summarizes the different types of WRA and describes diagnostic procedures, treatment, prevention, and approaches to patient management. It is not always easy to distinguish between OA and WEA. It is important to establish a diagnosis (of sensitizer-/irritant-induced OA or WEA) in order to prevent worsening of symptoms, as well as to prevent other workers from being exposed, by providing early treatment and counseling on social security and work-related issues.

Work-related asthma / Asma relacionada ao trabalho

ABSTRACT Work-related asthma (WRA) is highly prevalent in the adult population. WRA includes occupational asthma (OA), which is asthma caused by workplace exposures, and work-exacerbated asthma (WEA), also known as work-aggravated asthma, which is preexisting or concurrent asthma worsened by workplace conditions. In adults, the estimated prevalence of OA is 16.0%, whereas that of WEA is 21.5%. An increasing number of chemicals used in industrial production, households, and services are associated with the incidence of adult-onset asthma attributable to exposure to chemicals. This review article summarizes the different types of WRA and describes diagnostic procedures, treatment, prevention, and approaches to patient management. It is not always easy to distinguish between OA and WEA. It is important to establish a diagnosis (of sensitizer-/irritant-induced OA or WEA) in order to prevent worsening of symptoms, as well as to prevent other workers from being exposed, by providing early treatment and counseling on social security and work-related issues.

RESUMO A asma relacionada ao trabalho (ART) é um acometimento com elevada prevalência na população adulta. A ART inclui a asma ocupacional (AO), desencadeada pela exposição a um agente presente em um determinado ambiente de trabalho, e a asma agravada ou exacerbada pelo trabalho (AA/ET), que acomete indivíduos com antecedentes de asma ou que iniciaram um quadro de asma concomitante, mas sem relação causal com o ambiente de trabalho. Estima-se que 16,0% e 21,5% da asma no adulto sejam AO e AA/ET, respectivamente. O elevado e crescente número de substâncias químicas usadas na produção industrial, no uso domiciliar ou em serviços é responsável pela incidência de asma associada à exposição a agentes químicos na vida adulta. Este artigo de revisão descreve os principais tipos de ART, os procedimentos para seu diagnóstico, tratamento e prevenção e as condutas frente ao diagnóstico. Nem sempre é fácil a distinção entre AO e AA/ET. A importância do diagnóstico (AO ou AA/ET e asma induzida por sensibilizantes ou irritantes) tem relação com a adoção de medidas de prevenção para evitar que novos indivíduos sejam expostos e que os acometidos apresentem agravamento da doença, utilizando tratamento precoce e fornecendo orientação sobre aspectos previdenciários e trabalhistas.

[Analysis of direct economic burden of occupational asthma].

Objective: To analyze the direct economic burden of occupational asthma patients and provide economic basis for the government to rationally allocate health resources. Methods: In September 2019, colleted the case data of 53 patients diagnosed with occupational asthma who were hospitalized in our hospital from December 2008 to December 2018, and analyze the impact of gender, age, diagnosis time, ducation level, allergen type to the length of stay, hospitalization cost, medical technology diagnosis and treatment costs, western medicine costs, average daily hospitalization costs and other indicators. Results: The average length of hospitalization for occupational asthma patients was (38.7±8.1) days, and the average hospitalization cost was 14743 yuan, of which medical technology diagnosis and treatment costs, western medicine costs, and comprehensive medical service costs accounted for the top three, 42.5% (331977/781369) , 32.0% (249942/781369) , 19.6% (153268/781369) respectively. Hospitalization days for occupational asthma patients has decreased significantly in 2014-2018 (P<0.05) . There were no significant differences in hospitalization costs, medical technology diagnosis and treatment costs, western medicine costs, and average daily hospitalization costs for occupational asthma patients caused by different allergens (isocyanates, persulfates and phthalic anhydrides) (P>0.05) . Hospitalization days, hospitalization costs, medical technology diagnosis and treatment costs, western medicine costs, and average daily hospitalization costs of patients with moderate occupational asthma were significantly higher than those of mild patients (P<0.05) . Conclusion: Early detection of occupational asthma patients and early intervention can reduce the economic burden on patients and society.

The Burden of Work-related Asthma in Michigan, 1988-2018.

Rationale: Exposure to a variety of substances in the workplace can cause new-onset asthma or aggravate preexisting asthma, both of which are considered work-related asthma (WRA). Understanding trends in the nature and causes of WRA can assist in the diagnosis and management of adult patients with asthma.Objective: To describe trends over 31 years of WRA surveillance in Michigan.Methods: Michigan law requires reporting of all known or suspected cases of occupational disease. WRA was confirmed by review of a standardized telephone interview and patient medical records. Enforcement inspections at the workplaces of the WRA cases included air monitoring and evaluation for asthma and asthma symptoms among coworkers.Results: The Michigan surveillance program identified 3,634 WRA cases from 1988 to 2018, including nine deaths. The cumulative incidence rate of WRA decreased from 3.5 to 2.0 cases per 100,000 workers. Cases most frequently worked in manufacturing (56%), health care (12%), and education (4%). The cumulative incidence rate of WRA decreased in each of those three industries, while increasing in retail trade and accommodations and food services. The most common exposures to known asthma inducers were to cleaning agents and isocyanates; the percentage exposed to cleaning agents increased from 5% to 20%, and the percentage exposed to isocyanates decreased from 20% to 7%. Fifty-one percent had not applied for workers' compensation benefits. Only 5% of the 571 workplaces where air sampling was performed were above the allowable exposure limit. Fifteen percent (1,622 of 10,493) of coworkers of the index cases reported onset of asthma since beginning to work at the facility or being bothered at work by daily or weekly chest tightness, shortness of breath, or wheezing.Conclusions: The industries and exposures where Michigan adults develop WRA have changed during the past 31 years. The identification of WRA cases, including WRA deaths, underscores the need for continued vigilance to monitor changes in where and how workers are exposed to asthma-causing agents, physician consideration of workplace exposures in new-onset or worsening adult asthma, and adoption of workplace standards that reduce exposure and require workplace medical monitoring to prevent and reduce the morbidity and mortality of WRA.

Occupational asthma risk from exposures to toluene diisocyanate: A review and risk assessment.

BACKGROUND: Toluene Diisocyanate (TDI) is a known respiratory sensitizer linked to occupational asthma (OA). To better manage worker risks, an appropriate characterization of the TDI-OA dose-risk relationship is needed. METHODS: The literature was reviewed for data suitable for dose-response modeling. Previous study data were fit to models to derive prospective occupational exposure limits (OELs), using benchmark dose (BMD) and low-dose extrapolation approaches. RESULTS: Data on eight TDI-exposed populations were suitable for analysis. There were 118 OA cases in a population contributing 13 590 person-years. The BMD-based OEL was 0.4 ppb. The OEL based on low-dose extrapolation to working lifetime extra risk of 1/1000 was 0.3 ppb. CONCLUSIONS: This study synthesized epidemiologic data to characterize the TDI-OA dose-risk relationship. This approach yielded prospective OEL estimates below recent recommendations by the American Conference of Governmental Industrial Hygienists, but given significant study limitations, this should be interpreted with caution. Confirmatory research is needed.

Pneumococcal Vaccination Among Adults With Work-related Asthma.

INTRODUCTION: Pneumococcal vaccination is recommended for all adults with asthma and a Healthy People 2020 goal aims to achieve 60% coverage among high-risk adults, including those with asthma. Adults with work-related asthma have more severe asthma symptoms than those with non-work-related asthma and are particularly vulnerable to pneumococcal pneumonia. METHODS: To assess pneumococcal vaccination coverage by work-related asthma status among ever-employed adults aged 18-64 years with current asthma, data from the 2012-2013 Behavioral Risk Factor Surveillance System Asthma Call-back Survey for ever-employed adults (18-64 years) with current asthma from 29 states were examined in 2016. Adults with work-related asthma had ever been told by a physician their asthma was work-related. Pneumococcal vaccine recipients self-reported having ever received a pneumococcal vaccine. Multivariate logistic regression was used to calculate adjusted prevalence ratios and associated 95% CIs. RESULTS: Among an estimated 12 million ever-employed adults with current asthma in 29 states, 42.0% received a pneumococcal vaccine. Adults with work-related asthma were more likely to have received a pneumococcal vaccine than adults with non-work-related asthma (53.7% versus 35.0%, respectively, prevalence ratio=1.24, 95% CI=1.06, 1.45). Among adults with work-related asthma, pneumococcal vaccine coverage was lowest among Hispanics (36.2%) and those without health insurance (38.5%). CONCLUSIONS: Pneumococcal vaccination coverage among adults with work-related asthma and non-work-related asthma is below the Healthy People 2020 target level. Healthcare providers should verify pneumococcal vaccination status in their patients with asthma and offer the vaccine to those not vaccinated.

[Occupational asthma compensation in the Tunisian Center: cross-sectional study over a period of eight years]. / Asthme professionnel indemnisé dans le centre tunisien: étude ransversale sur huit ans.

INTRODUCTION: Our study aimed to highlight the epidemiological profile of patients compensated for occupational asthma in the Tunisian Center, to identify their professional characteristics and to determine compensation practices for this occupational disease. METHODS: We conducted an exhaustive retrospective study over a period of eight years. This case study included workers with occupational asthma diagnosed and compensated in the Tunisian Center by the only two medical commissions empowered to set rates for permanent partial disability caused by either a work-related injury or an occupational diseases in the seven central governorates. RESULTS: A total of 129 workers, with average age of 40.6 ± 7.75 years were compensated for occupational asthma during the study period. Sex ratio was 0.66. The most incriminated etiologic agents were vegetable dust pollution in the textile industry (75.2%), wood dust, flour and isocyanates. Nonspecific bronchial hyperreactivity was found in 38% of cases, a high rate of IgE in 14% of cases and positive skin prick test in 10.9% of cases. The average rate of permanent partial disability was 25.6 ± 14.2%. On the basis of the analytical study, this rate was related to patient's age and to the medical commission which had set this rate. CONCLUSION: This study of workers compensated for occupational asthma provides relevant data about epidemiological and clinical features of diagnosed patients and committee practices in particular, in term of application of the voluntary indicative scale, but it does not allow an assessment of the prevalence of this pathology which is often underestimated.

Assessment of work-related asthma prevalence, control and severity: protocol of a field study.

BACKGROUND: There are still uncertainties regarding the respective prevalence, diagnosis and management of occupational asthma (OA) and work-exacerbated asthma (WEA). There is as yet no standardized methodology to differentiate their diagnosis. A proper management of both OA and WEA requires tools for a good phenotyping in terms of control, severity and quality of life in order to propose case-specific therapeutical and preventive measures. Moreover, there is a lack of knowledge concerning their actual costs. METHODS: This project aims at comparing 3 groups of asthmatic subjects at work: subjects with OA, with WEA, and with non-work-related asthma (NWRA) in terms of control, severity and quality of life on the one hand, and estimating the prevalence of OA, WEA and NWRA in active workers and the economic costs of OA and WEA, on the other hand. Control will be assessed using the Asthma Control Test questionnaire and the daily Peak Exploratory Flow variability, severity from the treatment level, and quality of life using the Asthma Quality of Life Questionnaire. A first step will be to apply a standardized diagnosis procedure of WEA and OA. This study includes an epidemiological part in occupational health services by volunteering occupational physicians, and a clinical case-study based on potentially asthmatic subjects referred to ten participating University Hospital Occupational Diseases Departments (UHODD) because of a suspected WRA. The subjects' characterization with respect to OA and WEA is organized in three steps. In Step 1 (epidemiological part), occupational physicians screen for potentially actively asthmatics through a questionnaire given to workers seen in mandatory medical visit. In step 2 (both parts), the subjects with a suspicion of work-related respiratory symptoms answer a detailed questionnaire and perform a two-week OASYS protocol enabling us, using a specifically developed algorithm, to classify them into probably NWRA, suspected OA, suspected WEA. The two latter groups are referred to UHODD for a final harmonized diagnosis (step 3). Finally, direct and indirect disease-related costs during the year preceding the diagnosis will be explored among WRA cases, as well as these costs and the intangible costs, during the year following the diagnosis. DISCUSSION: This project is an attempt to obtain a global picture of occupational asthma in France thanks to a multidisciplinary approach.

Trends in Occupations and Work Sectors Among Patients With Work-Related Asthma at a Canadian Tertiary Care Clinic.

BACKGROUND: Work-related asthma (WRA) is the most common chronic occupational lung disease in the developed world. Several factors including sociodemographic status and occupation/industry increase the risks of developing WRA. In this study, we sought to identify changes in patterns and characteristics among patients with WRA over a 15-year period in an occupational lung disease clinic. METHODS: We performed a retrospective analysis of patients with WRA charts at the Occupational Lung Disease Clinic of a University Hospital in Toronto, Canada. Patients were divided into two periods classified by first attendance at the clinic 2000 through 2007 and 2008 through 2015. Comparisons between the two periods included: sociodemographic characteristics, smoking status, occupations, exposures, and submitted workers' compensation claims. RESULTS: Fewer occupational asthma cases were seen in the more recent period vs the earlier period (40 vs 74 cases), with a smaller reduction in work-exacerbated asthma cases (40 vs 58). The recent period included a significantly smaller proportion employed in the manufacturing industry and isocyanate-induced cases compared with the earlier period. An increased proportion were employed in health-care and education industries (primarily cleaners and teachers) in the recent period, consistent with a corresponding increased frequency of cleaning agents and dust exposures. CONCLUSIONS: The changes observed in work sectors in the patients with WRA in this clinic in Toronto are consistent with reductions reported in Ontario workers' compensation claims for occupational asthma and may relate to preventive measures. Cleaners and teachers should be a focus of further intervention measures for work-related asthma.

Redemption of asthma pharmaceuticals among stainless steel and mild steel welders: a nationwide follow-up study.

PURPOSE: The purpose was to examine bronchial asthma according to cumulative exposure to fume particulates conferred by stainless steel and mild steel welding through a proxy of redeemed prescribed asthma pharmaceuticals. METHODS: A Danish national company-based historical cohort of 5,303 male ever-welders was followed from 1995 to 2011 in the Danish Medicinal Product Registry to identify the first-time redemption of asthma pharmaceuticals including beta-2-adrenoreceptor agonists, adrenergic drugs for obstructive airway diseases and inhalable glucocorticoids. Lifetime exposure to welding fume particulates was estimated by combining questionnaire data on welding work with a welding exposure matrix. The estimated exposure accounted for calendar time, welding intermittence, type of steel, welding methods, local exhaustion and welding in confined spaces. Hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated using a Cox proportional hazards model adjusting for potential confounders and taking modifying effects of smoking into account. RESULTS: The average incidence of redemption of asthma pharmaceuticals in the cohort was 16 per 1,000 person year (95% CI 10-23 per 1,000 person year). A moderate nonsignificant increased rate of redemption of asthma medicine was observed among high-level exposed stainless steel welders in comparison with low-level exposed welders (HR 1.54, 95% CI 0.76-3.13). This risk increase was driven by an increase risk among non-smoking stainless steel welders (HR 1.46, 95% CI 1.06-2.02). Mild steel welding was not associated with increased risk of use asthma pharmaceuticals. CONCLUSION: The present study indicates that long-term exposure to stainless steel welding is related to increased risk of asthma in non-smokers.

Prevalence of Work-Related Asthma and its Impact in Primary Health Care.

BACKGROUND AND OBJECTIVE: To determine the prevalence of occupational asthma (OA) and work-exacerbated asthma (WEA) among asthmatic patients diagnosed in Primary Health Care (PHC). To analyze the impact at PHC level caused by under-diagnosis and inappropriate referral of OA. PATIENTS AND METHODS: A descriptive, cross-sectional multicenter study in patients aged between 16 and 64years diagnosed with asthma, according to their medical record; all were working or had worked, and were assigned to one of 16 PHC centers in a healthcare district. Based on the responses to the questionnaire completed at the study visit, which included a thorough review of the subject's entire working history, patients were classified into three categories by an expert in occupational asthma: OA, WEA or common asthma (CA). RESULTS: Three hundred and sixty-eight patients completed the questionnaire. The prevalence of OA was 18.2% (25% in men and 14.6% in women, P=.046), and 54 patients (14.7%) were classified as WEA. The proportion of patients with work-related asthma (WRA) was therefore 32.9%. Asthmatic patients with WRA took more sick leave than CA patients (P<.001). CONCLUSIONS: A high prevalence of WRA was found, mostly treated in PHC. Under-diagnosis of WRA is widespread in PHC.

Clinical aspects of work-related asthma: past achievements, persistent challenges, and emerging triggers.

OBJECTIVE: The aim of this article was to address common clinical questions pertaining to work-related asthma (WRA). METHODS: This review is based on a presentation on WRA at the American College of Chest Physicians Course on Clinical Aspects of Occupational and Environmental Lung Disease, held in Toronto in 2013, and supplemented by a PubMed search of publications to 2013. RESULTS: Seven clinical questions are addressed in relation to definitions, causes, diagnosis, management and emerging triggers, and challenges of WRA. CONCLUSIONS: Although knowledge is expanding in this area, there remain challenges and uncertainties, particularly in the prevention of WRA.

Respiratory disease associated with occupational inhalation to hop (Humulus lupulus) during harvest and processing.

BACKGROUND: There is little published evidence for occupational respiratory disease caused by hop dust inhalation. In the United States, hops are commercially produced in the Pacific Northwest region. OBJECTIVE: To describe occupational respiratory disease in hop workers. METHODS: Washington State workers' compensation claims filed by hop workers for respiratory disease were systematically identified and reviewed. Incidence rates of respiratory disease in hop workers were compared with rates in field vegetable crop farm workers. RESULTS: Fifty-seven cases of respiratory disease associated with hop dust inhalation were reported from 1995 to 2011. Most cases (61%) were diagnosed by the attending health care practitioner as having work-related asthma. Seven percent of cases were diagnosed as chronic obstructive pulmonary disease, and the remaining cases were diagnosed as allergic respiratory disorders (eg, allergic rhinitis) or asthma-associated symptoms (eg, dyspnea). Cases were associated with hop harvesting, secondary hop processing, and indirect exposure. The incidence rate of respiratory disease in hop workers was 15 cases per 10,000 full-time workers, which was 30 times greater than the incidence rate for field vegetable crop workers. A strong temporal association between hop dust exposure and respiratory symptoms and a clear association between an increase in hop dust concentrations and the clinical onset of symptoms were apparent in 3 cases. CONCLUSION: Occupational exposure to hop dust is associated with respiratory disease. Respiratory disease rates were higher in hop workers than in a comparison group of agricultural workers. Additional research is needed before hop dust can be confirmed as a causative agent for occupational asthma.

Diisocyanate and non-diisocyanate sensitizer-induced occupational asthma frequency during 2003 to 2007 in Ontario, Canada.

OBJECTIVE: To investigate proportions and outcomes of isocyanate and other causes of occupational asthma (OA) claims in Ontario, Canada, 2003 to 2007. METHODS: New accepted workers' compensation claims for OA compensated by the Ontario Workplace Safety and Insurance Board were retrospectively reviewed. RESULTS: There were 112 allowed claims for OA-30 (26.8%) from diisocyanates (ISO) and 82 (73.2%) from other causes (non-diisocyanates [N-ISO]). The most common occupations for ISO OA were production workers (50%). The most common agents in the N-ISO group were flour (13%) and metal dusts/fumes (10%). At a median time of 8 months postdiagnosis, 55% of ISO and 56.4% of N-ISO workers, respectively, were unemployed. CONCLUSIONS: Diisocyanates OA compensation claims in Ontario are recognized at a lower absolute number and proportion of all OA claims than those in earlier periods. More than half from all causes were unemployed at a median of 8 months postdiagnosis.

Occupational health disparities: a state public health-based approach.

BACKGROUND: This report used employment and public health surveillance data in Michigan to characterize work-related race/ethnic health disparities. METHODS: U.S. Census data were used to calculate the percent by race/Hispanic ethnicity in occupational groups ranked by three measures for potential work-related health risks. Disparities by race/ethnicity were generated from occupational health surveillance data. RESULTS: Blacks and Hispanics were over-represented in lower wage-higher manual-labor occupations and in highest risk occupations. Blacks were at greater risk of silicosis, work-related asthma, and work-related burns than whites, and Hispanics had higher rates of work-related acute fatal injuries and pesticide injury than non-Hispanics. CONCLUSIONS: Michigan employment data indicated that blacks and Hispanics were overly represented in lower paid and more hazardous jobs. Occupational health surveillance data confirmed disparate risks for some illnesses and injuries. This approach can be used in other states to bring awareness to policy makers and direct interventions.

[Occupational asthma--the case of bakers' asthma].

Occupational asthma (OA) is the most common of all occupational lung diseases in industrialized countries and its prevalence has been rising steadily. It is estimated that occupational factors account for one out of six cases of adult asthmatic patients causing significant morbidity, disability and costs. Due to its high prevalence and substantial health and socio-economic impacts OA represents a significant public health concern. OA can be divided into allergic and non allergic asthma. Allergic OA is further divided into IgE mediated and non IgE mediated. Baker's asthma (BA), is the leading cause of IgE mediated OA caused by high molecular weight antgens in industrialized countries. Innovations in the baking industry during the last few decades have led to the introduction of new allergens inducing OA. OA is potentially preventable, through early diagnosis and exposure cessation interventions. Thus, clinicians should consider the occupational history in every adult patient presenting with newly diagnosed asthma.

Medical surveillance for prevention of occupational asthma.

PURPOSE OF REVIEW: Because there is sufficient knowledge of its environmental determinants, occupational asthma is a disease that ought to be largely preventable; yet its incidence in many settings remains unacceptably high. Here we review one approach to prevention: the routine use of health surveillance in exposed workforces. RECENT FINDINGS: Health surveillance is widely practised but there is little evidence that it is used strategically to reduce disease incidence. There are several barriers to the effective use of its various components, chiefly symptoms questionnaires and spirometry. Cost-benefit analyses may help to increase the uptake of industry-wide workplace interventions. SUMMARY: The effective use of health surveillance for occupational asthma continues to be challenging and there remains relatively little published evidence that will encourage those involved to use it more efficiently. Useful advances could be made by greater collaboration between employers, employee organizations, legislators and researchers.

Audit of the recording of occupational asthma in primary care.

BACKGROUND: Occupational asthma (OA) remains common; 1 in 10 cases of adult-onset asthma is due to work. Health outcomes are better with early diagnosis, but there is considerable delay, largely due to lack of enquiry about work effect in primary care. National guidelines (2008) recommend asking two screening questions, which together have a high sensitivity in identifying OA. AIMS: To audit how working-age asthmatics are currently screened for OA in a local primary care population. METHODS: An audit of the electronic patient records of working-age asthmatics, from four Birmingham primary care practices was undertaken. Practice-level data (list size, gender, prevalence of asthma and OA and socio-economic status) and patient-level data (gender, age, onset, occupation and work-effect enquiry and lung function) were collected. RESULTS: The total practice population was 27,295 of which 17,564 (64%) were of working age. The audit sample was 396 of whom 49% were male. The prevalence of asthma in working-age adults was 12% (8-15%) and the prevalence of OA in working-age asthmatics was 0.3% (0-0.8%). Occupation was recorded in only 55/396 (14%) cases with very few (2) documented within the asthma-review template. Occupation was only recorded in 13/55 adult-onset asthmatics in high-risk occupations. Of 396, 9 (2%) had any work-effect enquiry and 4 patients had work-effect enquiry at diagnosis in those with traceable notes (n = 117). CONCLUSIONS: The prevalence of OA was low, suggesting under-diagnosis plus under-reporting in primary care. Occupation and work-effect enquiry is lacking despite guidelines for identifying OA. Existing electronic templates for recording asthma review could be modified to include these elements.

Prevention of laboratory animal allergy in the United States: a national survey.

OBJECTIVE: Respiratory allergy to laboratory animals is a common and preventable occupational health problem. This study documents current laboratory animal allergy (LAA) prevention programs in the United States. METHODS: An online survey was e-mailed to designated institutional officials at laboratory animal facilities identified by the National Institutes of Health Office of Laboratory Animal Welfare. RESULTS: A total of 198 organizations responded and more than 80% required the use of uniforms and gloves to control exposure. Respirators were required by 25% of organizations. Medical surveillance was mandated by 58% of organizations (70% for organizations with at least 100 employees working with animals). Work restriction practices varied. Only 25% of organizations reported knowing the prevalence (range: 0% to 75%) and 29% reported knowing the incidence of LAA (range: 0% to 18%). CONCLUSIONS: There is broad variation in policy and practice to prevent LAA. An evidence-based consensus would ensure greater protection of workers.

Assessment of public health impact of work-related asthma.

BACKGROUND: Asthma is among the most common chronic diseases in working-aged populations and occupational exposures are important causal agents. Our aims were to evaluate the best methods to assess occurrence, public health impact, and burden to society related to occupational or work-related asthma and to achieve comparable estimates for different populations. METHODS: We addressed three central questions: 1: What is the best method to assess the occurrence of occupational asthma? We evaluated: 1) assessment of the occurrence of occupational asthma per se, and 2) assessment of adult-onset asthma and the population attributable fractions due to specific occupational exposures. 2: What are the best methods to assess public health impact and burden to society related to occupational or work-related asthma? We evaluated methods based on assessment of excess burden of disease due to specific occupational exposures. 3: How to achieve comparable estimates for different populations? We evaluated comparability of estimates of occurrence and burden attributable to occupational asthma based on different methods. RESULTS: Assessment of the occurrence of occupational asthma per se can be used in countries with good coverage of the identification system for occupational asthma, i.e. countries with well-functioning occupational health services. Assessment based on adult-onset asthma and population attributable fractions due to specific occupational exposures is a good approach to estimate the occurrence of occupational asthma at the population level. For assessment of public health impact from work-related asthma we recommend assessing excess burden of disease due to specific occupational exposures, including excess incidence of asthma complemented by an assessment of disability from it. International comparability of estimates can be best achieved by methods based on population attributable fractions. CONCLUSIONS: Public health impact assessment for occupational asthma is central in prevention and health policy planning and could be improved by purposeful development of methods for assessing health benefits from preventive actions. Registry-based methods are suitable for evaluating time-trends of occurrence at a given population but for international comparisons they face serious limitations. Assessment of excess burden of disease due to specific occupational exposure is a useful measure, when there is valid information on population exposure and attributable fractions.