Occupational Asthma: A Longitudinal Study on the Clinical and Socioeconomic Outcome After Diagnosis

doi:10.1378/chest.115.1.249

Chest

Volume 115, Issue 1, January 1999, Pages 249-256

https://doi.org/10.1378/chest.115.1.249 Get rights and content

Aim

To evaluate the clinical outcome and socioeconomic consequences of occupational asthma (OA).

Subjects and methods

Twenty-five patients with OA both to high- and low-molecular-weight agents (3 and 22, respectively) confirmed by specific inhalation challenge were followed up for 12 months after the diagnosis. Upon diagnosis, each patient received a diary on which to report peak expiratory flow rate (PEFR), symptoms, drug consumption, expenses directly or indirectly related to the disease, as well as information regarding personal socioeconomic status. At each follow-up visit (1, 3, 6, and 12 months), the patients underwent clinical examination, spirometry, methacholine (Mch) challenge, and assessment of diary-derived parameters and socioeconomic status. Asthma severity (AS) was classified into four levels, based on symptoms, drug consumption, and PEFR variability.

Results

At 12 months, 13 patients (group A) had ceased exposure; the remaining 12 patients (group B) continued to be exposed. At diagnosis, FEV₁ percent and provocative dose causing a 20% fall in FEV₁ (PD₂₀) of Mch were lower in group A than in group B; patients of group A were also characterized by significantly higher basal AS levels. At 12 months, no significant variation in FEV₁ percent or PD₂₀ was found for either group, while AS levels improved in both groups, the change being more marked for group A than group B. Pharmaceutical expense at 12 months significantly (p < 0.05) decreased, as compared with the first month, in group A, whereas it tended to increase in group B. In group A, 9 of 13 subjects had reported a deterioration of their socioeconomic status as compared with 2 of 12 in group B (p < 0.01). A significant loss of income was registered in patients of group A (median 21.45, 25th to 75th percentiles 16.9 to 25.8 Italian liras × 10⁶ on the year preceding diagnosis and 15.498, 10.65 to 21.087 Italian liras × 10⁶ on the year after diagnosis; p < 0.01), whereas no significant change was seen for patients in group B.

Conclusions

In OA, cessation of exposure to the offending agent results in a decrease in asthma severity and in pharmaceutical expenses, but it is associated with a deterioration of the individual's socioeconomic status (professional downgrading and loss of work-derived income). There appears to be a great need for legislation that facilitates the relocation of these patients.

Section snippets

Study Design

Subjects were examined at the time of diagnosis of OA and reevaluated at 1, 3, 6, and 12 months after diagnosis. Allergy skin tests were performed at time of diagnosis. For the duration of the study, all patients reported peak expiratory flow (PEF) values on a personal asthma diary together with symptoms, drug intake, medical events, and disease-related costs (see below). At time of diagnosis and at each following visit, clinical examination, spirometry, and bronchial challenge with

Results

Three subjects refused to be enrolled in the study while four others did not come to control visits (two preferred to be followed up in another center, while two were no longer interested in participating in the study). The remaining 25 subjects completed the study. Among participants, OA was due to high-molecular-weight (HMW) agents in 3 subjects and to low-molecular-weight (LMW) agents in 22 (isocyanates in 9 of them) (Table 1). In the seven nonparticipants, the causal agents were LMW agents.

Discussion

In this prospective study, we followed up a group of subjects with OA due to various agents at regular intervals of time for 1 year after the diagnosis, recording at each time point their clinical, functional, employment, and financial status.

Removal from exposure to the offending agent is recommended as the first-line measure for the management of OA.3, 4 Our data show that in Italy⁷ as in other countries5, 8 where this procedure is not mandatory, this occurs only in a limited proportion of

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Cited by (87)

Occupational asthma caused by high- and low-molecular weight agents in an auto body worker
2018, Annals of Allergy, Asthma and Immunology
Understanding health beliefs and behaviour in workers with suspected occupational asthma
2015, Respiratory Medicine
Citation Excerpt :
In the study by Bradshaw et al. [9], a significant proportion of workers with occupational asthma continued working with asthmagens that caused ongoing symptoms, since the fear of financial loss through job loss was greater than the concern for their own respiratory health. This is understandable as around 85% of workers who leave their employment (to become unemployed or find alternative work) suffer a loss of income of 22–50% [28–31]. Additionally, a large proportion of the costs of occupational asthma are borne by the individual worker (49%) rather than the employer (3%), who therefore has little incentive to act [5].
Long delays from symptom onset to the diagnosis of occupational asthma have been reported in the UK, Europe and Canada and workers are often reluctant to seek medical help or workplace solutions for their symptoms. Reducing this delay could improve workers' quality of life, and reduce the societal cost of occupational asthma. This study aimed to explore reasons behind such delays.
A purposive sample of 20 individuals diagnosed with, or under investigation for, occupational asthma (median age = 52; 70% male; 80% white British) undertook a single semi-structured interview. Interviews were transcribed verbatim and thematic analysis was undertaken in order to explore health beliefs and identify barriers to diagnosis.
Four themes were identified: (1) workers' understanding of symptoms, (2) working relationships, (3) workers' course of action and (4) workers' negotiation with healthcare professionals. Understanding of symptoms varied between individuals, from a lack of insight into the onset, pattern and nature of symptoms, through to misunderstanding of what they represented, or ignorance of the existence of asthma as a disease entity. Workers described reluctance to discuss health issues with managers and peers, through fear of job loss and a perceived lack of ability to find a solution. The evolution of workers' understanding depended upon how actively they looked to define symptoms or seek a solution. Proactive workers were motivated to seek authoritative help and negotiate inadequate healthcare encounters with GPs.
Understanding workers' health beliefs will enable policy makers and clinicians to develop better workplace interventions that may aid diagnosis and reduce delay in identifying occupational asthma.
Evolution of occupational asthma: Does cessation of exposure really improve prognosis?
2014, Respiratory Medicine
Citation Excerpt :
Occupational asthma (OA) is the most frequent work-related respiratory disease in developed countries [1,2] and it is estimated that roughly 10% cases of bronchial asthma and between 15 and 25% of adult onset asthma may be of occupational origin [3,4].
To assess the evolution of occupational asthma (OA) depending on whether the patient avoids or continues with exposure to the offending agent.
Study in patients diagnosed with OA using a specific inhalation challenge. Patients underwent the following examinations on the same day: clinical interview, physical examination, forced spirometry, methacholine test and determination of total IgE. Clinical improvement, deterioration or no change were defined according to the changes seen on the GINA severity scale at the time of diagnosis.
Of the 73 patients finally included, 55 had totally ended exposure and 18 continued to be exposed at work. Clinical improvement was observed in 47% of those who had terminated exposure and in 22% of those who remained exposed; clinical deterioration was observed in 14% and 17% respectively (p = 0.805). Logistical regression analysis, including the type of agent and the persistence or avoidance of exposure among the variables, did not show any predictive factors of clinical evolution. Similarly, the changes in FEV₁ and in bronchial hyperresponsiveness were not associated with the avoidance or continuation of exposure to the causative agent.
Avoiding exposure to the causative agent in patients with OA does not seem to improve prognosis in this disease. Despite these findings, there is insufficient evidence to recommend a change in current management guidelines.
Work-Related Asthma: A Case-Based Approach to Management
2011, Immunology and Allergy Clinics of North America
Citation Excerpt :
The published medical literature documents a few examples of patients sensitized to LMW antigens who remained in their jobs with medical follow-up. One study of 25 patients with OA, of whom 22 had asthma caused by an LMW chemical, showed no significant differences in the percentage of predicted forced expiratory volume in 1 second or methacholine PD20 compared with baseline for the 12 patients who remained in their jobs, or the 13 with more severe disease who left employment.15 Nonetheless, the outcome of LMW asthma in patients who are not removed from exposure is often one involving persistent symptoms, need for medication, and bronchial hyperresponsiveness, as in isocyanate-induced asthma31,32 and western red cedar asthma.4,33
Occupational agents
2009, Asthma and COPD
Occupational agents (OA) is a disease characterized by variable airflow limitation and/or airway hyperresponsiveness and/or inflammation due to causes and conditions attributable to a particular occupational environment and not to stimuli encountered outside the workplace. Over 300 agents in the workplace have been implicated in causing asthma. The agents can be divided into two groups according to the pathogenic mechanisms: those that give rise to asthma by immunological mechanisms and those by nonimmunological mechanisms. Agents in the former group can cause asthma by immunoglobulin (Ig)E-dependent or IgE-independent mechanisms. Irritant-induced asthma (IIA) is a type of OA caused by an apparently nonimmunological mechanism. Many patients may have been exposed to multiple sources, and the relative contributions of each may be impossible to disentangle. COPD is the symptomatic and functional consequence of chronic exposure to these polluted air sources. Therefore, it seems appropriate to pose a definition for occupational COPD that allows it to coexist with “smoking-induced COPD” or “urban air pollution-induced COPD.” Asthma is a common respiratory occupational ailment. Whereas improvement in diagnostic tools and pathophysiological mechanisms still need to be considered, emphasis should be put on prevention programs through identification and application of permissible respirable levels and of affected subjects at an early stage of sensitization or disease to prevent long-term sequelae of permanent asthma.
Costs of occupational asthma in the UK
2011, Thorax
To estimate the social costs of occupational asthma in the UK.
A desk-top approach using cost-of-illness methodology was employed, defining direct and indirect lifetime costs for six scenarios: a male and a female worker each exposed to isocyanates, latex and biocides (eg, glutaraldehyde) or flour. The numbers of new cases annually in each industry were estimated from Survey of Work-related and Occupational Respiratory Disease (SWORD) data. The main outcome measure was the current value total working lifetime costs of new cases annually for each scenario.
Assuming 209 new cases of occupational asthma in the six scenarios in the year 2003, the present value total lifetime costs were estimated to be £25.3–27.3 million (2004 prices). Grossing up for all estimated cases of occupational asthma in the UK in 2003, this came to £70–100 million. About 49% of these costs were borne by the individual, 48% by the state and 3% by the employer.
The cost to society of occupational asthma in the UK is high. Given that the number of newly diagnosed cases is likely to be underestimated by at least one-third, these costs may be as large as £95–135 million. Each year a new stream of lifetime costs will be added as a newly diagnosed cohort is identified. Approaches to reduce the burden of occupational asthma have a strong economic justification. However, the economic burden falls on the state and the individual, not on the employer. The incentive for employers to act is thus weak.

View all citing articles on Scopus

: Supported by grant ICS-57.3/RF92/719, from the Italian Ministry of Health.

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Chest

Occupational and Environmental Lung DiseaseOccupational Asthma: A Longitudinal Study on the Clinical and Socioeconomic Outcome After Diagnosis

Aim

Subjects and methods

Results

Conclusions

Section snippets

Study Design

Results

Discussion

Respir Med

Chest

Ann Allergy Asthma Immunol

Am J Med

J Allergy Clin Immunol

Chest

Guidelines for the diagnosis of occupational asthma

Clin Exp Allergy