Review of Diagnostic Challenges in Occupational Asthma

Ecuadorian Provinces with High Morbidity and Mortality Rates Due to Asthma among the Working-Age Population: An Ecological Study to Promote Respiratory Health

Asthma is a significant public health concern. This study identified the provinces with the highest morbidity and mortality rates due to asthma among the working-age population (15-69 years) in the Republic of Ecuador. The secondary objective was to explain the possible differences attributable to occupational exposure. This nationwide ecological study was conducted in 24 provinces between 2016 and 2019. Government databases were used as sources of information. Age-standardized rates were calculated for codes J45 and J46. The hospitalization morbidity rate for asthma decreased from 6.51 to 5.76 cases per 100,000 working-age population, and the mortality rate has consistently been low and stable from 0.14 to 0.15 deaths per 100,000 working-age population. Geographic differences between the provinces were evident. The risk of hospitalization and death due to asthma was higher in the Pacific coast (Manabí with 7.26 and 0.38, Esmeraldas with 6.24 and 0.43, Los Ríos with 4.16 and 0.40, El Oro with 7.98 and 0.21, Guayas with 4.42 and 0.17 and the Andean region (Azuay with 6.33 and 0.45, Cotopaxi (5.84 and 0.48)). The high rates observed in provinces with greater agricultural and industrial development could be national heterogeneity's main determinants and act as occupational risk factors. The contribution of occupational hazards in each province should be examined in depth through ad hoc studies. The findings presented here provide valuable information that should prompt further detailed studies, which will assist in designing public policies aimed at promoting and safeguarding the respiratory health of the population, particularly that of workers. We believe that this study will inspire the creation of regional networks for the research and surveillance of occupational health.

[Occupational obstructive airway diseases: How can early diagnosis be made to avoid chronic courses?]

Since abolishing the obligation to terminate the harmful professional activity from January 1st, 2021 onwards for some occupational diseases including obstructive respiratory diseases in Germany, the recognition of occupational diseases coded under 4301, 4302 and 1315 according the Occupational Diseases Ordinance has increased significantly. By the time these diseasese are recognized, they are usually already at an advanced stage. Therefore, early detection will play a greater role in the future, as the statutory accident insurance can offer individual preventive measures in order to minimize the consequences of illness and thus also the socio-economic burden. However, precursors of such obstructive airway diseases are often overlooked. For optimizing early detection, the statutory accident insurance worked out an early notification procedure for the respiratory tract - comparable to the already well-established dermatological procedure. "Early cases" from the pilot regions can be reported there; to qualify for being reported as early cases, patients must persue insured professional activity with potential effects on the respiratory tract and suffer from a disease of the upper or lower respiratory tract according to the ICD-10 code (e.g. J31.0 chronic rhinitis).

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.

Inhalation Challenge Tests in Occupational Asthma: Why Are Multiple Tests Needed?

Occupational and environmental lung diseases are on the rise because of the widespread use of various toxic agents in industry. Asthma etiopathogenesis is unclear because of exposure to high and low molecular agents in workplaces. Approximately 15-25% of asthma in adults is reported to be related to occupational exposure. The prevalence of occupational asthma (OA) is predicted to be high. The difficulties in diagnosing OA results in inadequate treatment, permanent airway damage, and medicolegal and social problems. As with other occupational diseases, it is necessary to demonstrate a direct causal relationship between the suspected agent and OA. Spirometry, peak expiratory flow rate, and/or non-specific bronchial hyperresponsiveness are frequently used to show airway hyperresponsiveness at the workplace and away from work. However, there are some controversies about the specificity and sensitivity of these test methods. Furthermore, these tests do not identify the exposure agent, which could be the causative agent. Specific inhalation challenge (SIC) tests that demonstrate the direct causal relationship are currently the gold standard. However, their positive and negative predictive values have not yet been established; therefore, many low molecular weight agents could cause late or atypical reactions. Therefore, a negative SIC test cannot exclude the disease. This review describes the procedures for the SIC test and discusses the importance of using the combined test methods with the SIC test.

Shorter time to clinical decision in work-related asthma using a digital tool

PEF curves are a useful but cumbersome tool in diagnosing work-related asthma. Using a digital spirometer and smartphone app, time to clinical decision could be shortened by 6-7 weeks. Physician's time spent analysing PEF data is also shortened. https://bit.ly/3d5SY78.

Adult Asthma among Workers in Ontario. Results from the Occupational Disease Surveillance System

Rationale: Given that approximately 15% of new-onset adult asthma cases originate because of exposures in the workplace, there is a need for systematic and ongoing monitoring of risk among workers. Objectives: To characterize the risk of new-onset adult asthma among workers in Ontario. Methods: We used 575,379 provincial accepted time-loss workers' compensation claimants data linked to physician billing data. Workers aged 15 to 65 years with a nonasthma compensation claim between January 1, 2002, and December 31, 2013, were eligible for inclusion. Cohort entry corresponded to the date of the claim. The case definition required two or more records for asthma within a 12-month period, within a 3-year time window after cohort entry. A 3-year washout period preceding cohort entry was used to exclude prevalent cases. Workers at risk of new-onset adult asthma were followed from cohort entry date to date of diagnosis, emigration, age 65 years, death, or end of study period. Cox regression models were used to generate birth year- and sex-adjusted hazard ratios (HRs) by occupation, industry, and exposures identified using a job exposure matrix. Sex-stratified risk estimates were also generated. Results: Increased risks were detected among well-recognized groups, including bakers (HR, 1.60; 95% confidence interval [CI], 1.22-2.09) and painters and decorators (HR, 1.67; 95% CI, 1.23-2.28). In the job exposure matrix analysis, flour and isocyanates were associated with increased risk of asthma. Concrete finishers (HR, 1.93; 95% CI, 1.12-3.32) and shipping and receiving clerks (HR, 1.21; 95% CI, 1.03-1.43) also showed elevated risk, whereas results varied across woodworker groups. Decreased risks were detected for nursing and farming groups. Conclusions: This practical data linkage approach was successful for examining associations across hundreds of jobs. Unexpected and previously unrecognized findings deserve further investigation and emphasize the importance of an ongoing system to guide research as well as prevention.

Performance of specific immunoglobulin E tests for diagnosing occupational asthma: a systematic review and meta-analysis

OBJECTIVES

To determine the test performance parameters for the retrievable range of high-molecular-weight (HMW) and low-molecular-weight (LMW) occupational allergens and to evaluate the impact of allergenic components and the implementation of measures for test validation.

METHODS

A protocol with predefined objectives and inclusion criteria was the basis of an electronic literature search of MEDLINE and EMBASE (time period 1967-2016). The specific inhalation challenge and serial peak flow measurements were the reference standards for the specific IgE (sIgE) test parameters. All of the review procedures were reported according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

RESULTS

Seventy-one studies were selected, and 62 entered meta-analysis. Pooled pairs analysis indicated a sensitivity of 0.74(95% CI 0.66 to 0.80) and specificity of 0.71(95% CI 0.63 to 0.77) for HMW allergens and a sensitivity of 0.28(95% CI 0.18 to 0.40) and specificity of 0.89(95% CI 0.77 to 0.95) for LMW allergens. Component-specific analysis improved the test parameters for some allergens. Test validation was handled heterogeneously among studies.

CONCLUSION

sIgE test performance is rather satisfactory for a wide range of HMW allergens with the potential for component-specific approaches, whereas sensitivity for LMW allergens is considerably lower, indicating methodological complications and/or divergent pathomechanisms. A common standard for test validation is needed.

An increase of fractional exhaled nitric oxide after specific inhalation challenge is highly predictive of occupational asthma

PURPOSE

An increase of fractional exhaled nitric oxide (FeNO) has been described after specific inhalation challenges (SICs) with occupational allergens, but the clinical role of FeNO measurements before and after SIC is unknown. It was the aim of this study to assess the diagnostic accuracy of FeNO measurements before and after SIC in subjects with suspected occupational asthma (OA).

METHODS

One hundred forty-eight patients with suspected OA were examined by SIC with various occupational allergens. Subjects were assigned to pulmonary responders, nonresponders or doubtful by standard lung function criteria. FeNO was measured before SIC (baseline) and 24 h afterwards. Subjects with negative or doubtful SIC but increase of FeNO were evaluated individually by an overall expert rating. Effect modifiers of FeNO increases were assessed by regression analyses.

RESULTS

Thirty-one patients (21%) were classified as pulmonary responders, 105 (71%) as nonresponders and 12 (8%) as doubtful. With the pulmonary responder status as gold standard an increase of FeNO ≥ 13 ppb showed a specificity of 0.9 and a sensitivity of 0.5. Seventeen subjects with negative or doubtful responder status showed such an increase of FeNO, among them 13 subjects with definitive or probable OA after expert rating. Regression analyses revealed no significant modifiers for the FeNO increase.

CONCLUSION

An increase of FeNO after SIC is highly predictive of OA and should be regarded as an additional criterion for the interpretation of SIC with occupational agents.