Exposure to respiratory irritant substances occurs in a wide range of sectors, from heavy industry to construction, transport, cleaning and agriculture. It is estimated that some hundreds of thousands of employees may be exposed to these substances in Finland.
Cases where exposure levels are high and the causal relationship is clear can be considered an occupational disease. In Finland, between five and ten cases of occupational asthma caused by irritants (in other words, irritant-induced asthma) are recorded per year, and the number of cases is increasing. Based on previous, small-scale follow-up studies, the long-term prognosis for irritant-induced asthma is poor. According to our experience, the work ability and functional capacity of those affected are quite often permanently reduced.
In this study, we will gain new information about the professions, industries and work tasks connected to the risk of irritant-induced asthma in Finnish work life. This information will be extremely important in the prevention of the disease. The research results can be used to provide information for workplaces on protective measures, improvement of working conditions and accident prevention. They can also help prevent less severe respiratory diseases caused by respiratory irritants as well as diseases not commonly identified as occupational diseases.
We will also analyse how the exposure has been assessed. Our aim is to improve the diagnostics of occupational asthma by making the assessment methods consistent and as reliable as possible.
A better understanding of irritant-induced asthma as a disease can promote the diagnostics, treatment, rehabilitation and work ability of those affected.
Measures in the project
In this project, we will carry out a follow-up study of a patient cohort using the patient register of the Helsinki branch of the Finnish Institute of Occupational Health. The study group consists of irritant-induced asthmas and, as the control group, chemical and grain-induced asthmas developed by sensitization in 2006–2018, as they are highly representative of asthma developed through an immunological mechanism. The study utilizes patients' medical records, patient interviews and pulmonary function tests.
We have asked the HUS ethics committee for a statement regarding the study. Participation in the study is voluntary, and the research subjects may temporarily or permanently cancel their participation in the study at any point.
In this study, we will:
- retroactively collect comprehensive information on the exposure event and the course of the disease from medical records;
- use a follow-up study to interview the research subjects about their current situation with the asthma, their work ability, quality of life and mood; and
- use clinical studies in the follow-up study to determine the current status of the asthma.
Comparing irritant-induced asthma with occupational asthma developed through sensitization provides new information on the clinical presentation of the disease and typical medical findings. This is relevant for the diagnostics and treatment of the disease. Extensive data can also be used to assess whether there are differences between cases caused by different exposure agents. The follow-up study will be used to collect data on the prognosis of patients and their continued employment.
Materials and techniques
The patient data of the Finnish Institute of Occupational Health used in the study covers all the approximately 70 irritant-induced asthmas diagnosed in Finland over 18 years. The cases have been thoroughly studied and a great deal of information on occupational exposure resulting in asthma has been collected from the workplace and through interviews with patients. The asthmas were diagnosed based on high-quality pulmonary function tests. The amount of data is considerable: such a large set of patient data has not previously been analysed, even internationally.
Project manager, chief physician
Finnish Institute of Occupational Health and The Finnish Work Environment Fund