Background: Medical surveillance including spirometry is periodically performed among workers who are exposed to agents causing occupational asthma in Finland. Surveillance has been shown to detect occupational asthma at an earlier stage, however only a few studies have assessed its benefits.
Aims: Our aim of was to assess the role of surveillance and spirometry in intiating occupational asthma examinations. We also evaluated the quality of the spirometry.
Methods: We retrospectively reviewed the medical files of 60 patients diagnosed with sensitizer induced occupational asthma at the Finnish Institute of Occupational Health in 2012-2014 and participated surveillance program. Information about work exposure, respiratory symptoms, the occupational or primary health care visit initiating examinations, first spirometry and the details of the diagnosis were collected.
Results: Altogether 11 (18%) cases were detected in medical surveillance and 49 (82%) at non-surveillance doctor's practice. The median delay from the onset of asthma symptoms to the diagnosis was 2.2 years, it did not differ between these groups. No case was detected based on abnormal spirometry without respiratory symptoms. However, 5 (8%) of the patients reported solely work related rhinitis symptoms. The spirometry was normal in half of the cases, the quality criteria were fulfilled in 86% of the tests.
Conclusions: Our results support the view that spirometry for non-symptomatic workers is not beneficial in occupational asthma surveillance and highlight the importance of work related nasal symptoms in detecting occupational asthma.