Observations of Occupational Asthma and Work-Exacerbated Asthma

Potential interventions to reduce the time to the diagnosis of WRA include changing regulatory or enforcement policies, better access to compensation, employer education, education of primary treating physicians, and education of pulmonary specialists on the diagnosis and management of WRA. This study extends previous findings by assessing larger groups, including both OA and WEA patients, from populations in clinics and persons who had filed workers compensation claims. Personal and work factors were associated with longer diagnostic milestones. Among those patients with OA, men and those with lower education reported a longer time to first physician visit, perhaps due to greater concerns about the socioeconomic impact. A shorter time to physician assessment and diagnosis was associated with worker knowledge of agents at work that could affect their asthma and the presence of a health-and-safety program, suggesting a benefit from these factors for earlier recognition of WRA.


There are several limitations to the interpretation of these data. First, the questionnaire was administered after the diagnosis was reached and is potentially subject to recall bias. As expected, there was a significant difference between the median time to diagnosis of OA and that for WEA (ie, those patients with preexisting asthma should already have had medical follow-up and should have been seen by a physician sooner due to a worsening of their condition), so the potential for inaccurate recollection may be greater among patients in the OA group. The onset of OA may be gradual, and the exact onset date may be difficult to determine. However, the results were assessed separately for each group, and the groups were not directly compared for outcome determinants.



OA and WEA groups differed by the source of identification for this study. Those patients with OA were more likely to have a greater amount of information available in their files and to have undergone investigations to confirm the diagnosis, usually requiring specialist referral and reflecting the relative predominance of OA patients from the hospital clinic. In contrast, WEA patients were likely to have received their diagnosis from a primary care physician based on symptoms, and their short time to first physician visit was consistent with an acute exacerbation. Although WEA subjects were most often identified through the Ontario WSIB and OA was most often diagnosed in a hospital-based clinic, OA patients also had WSIB claims. All subjects were clearly informed that the research study would not influence their compensation claim, minimizing the likelihood that responses varied with identification source. The proportions of OA/WEA, although similar to that previously found by us among WSIB-accepted asthma claims, did not necessarily reflect the proportion of WEA among current WSIB-ac-cepted claims since we aimed to enroll similar numbers of patients from the clinic and the WSIB.

There could be recall bias in the reporting of workplace factors such as surveillance programs and safety training. However, within each group of OA or WEA patients, there would not be expected to be systematic differences in bias for such reporting. As expected, screening programs at work and diisocyanate exposures were reported more often by the OA group (Ontario has mandated medical surveillance for diisocyanates). Only a minority of patients reported that screening included questionnaires and pulmonary function tests, perhaps reflecting diisocyanate exposure in small companies such as autobody repair shops with difficulty complying with medical surveillance.

See also  Understanding the Importance of Asthma Inhalers - Types, Costs, and Solutions


The short median time to first seeing a physician (1 month) for WEA demonstrates opportunities for physicians to intervene early in the course of WEA, to optimize asthma control, to provide education as to possible work relationships, and to reduce exposures at work to respiratory triggers. Even in OA patients, the 3-month median time to first physician visit suggests opportunities for primary care physicians to question patients about work relationships and to intervene relatively early. Although 53% of those patients with OA reported that their physician referred them for testing as soon as the diagnosis was suspected, further primary care physician education might enhance early referral for more rapid diagnostic testing, thus allowing earlier diagnosis and intervention to improve prognosis. There has been a self-identified need for improved physician knowledge of WRA in Ontario both among primary care physicians and pulmonary specialists.

Our findings suggest the need for additional studies to identify factors that may prevent the recognition of WRA. Although the diagnosis is likely to be missed in a significant subset of workers, our study included only those persons who had received a diagnosis of WRA. Factors associated with lack of diagnosis could only be examined in community-based or worker-based studies. Also, our findings may not be generalizable to workers in countries or regions without universal health-care access or with different physician or compensation systems.

More articles on this topic you may find here:

Occupational Asthma and Work – Exacerbated Asthma
Stydying of Occupational Asthma and Work-Exacerbated Asthma
Outcomes of Occupational Asthma and Work-Exacerbated Asthma

See also  Outcomes of Studies Concerning Patients with Asthma, Aspirin Intolerance, and Nasal Polyps