Asbestos exposure can cause different kinds of diseases:
- pneumoconiosis, diffuse pulmonary fibrosis, i.e. asbestosis
- benign pleural thickening and fibrosis, pleural plaques
- cancers, lung cancer, mesothelioma (cancer of pleura and peritoneum), larynx cancer and ovarian cancer
Note that all types of asbestos can cause any of these diseases. The risk of developing an asbestos-related disease depends on individual susceptibility and the amount, level (asbestos fibres/ cm3) and duration of exposure (years).
Only moderate and heavy exposure, usually 20‒30 years in construction or shipyard work, can cause asbestosis and doubles the risk of lung cancer. However, benign pleural plaques and malign mesothelioma can develop after shorter exposures. Thus there is theoretically no safe limit for asbestos exposure. Asbestos diseases develop slowly and are most commonly seen among older men.
In practice, the risk of mesothelioma is very low, and people should not panic if accidental exposure occurs. Even though the use of asbestos has been totally banned in Finland since 1994, new cases of asbestos-related diseases (ARD) are notified yearly. In 2012, a total of 4404 cases of occupational diseases or suspected occupational diseases were notified to the Finnish Institute of Occupational Health’s Register of Occupational Diseases (FROD). Among these were 726 cases of recognized and suspected occupational diseases caused by asbestos.
The most common (509 cases) was pleural plaques and adhesions, which rarely cause symptoms or observable reduction in lung function. There were 62 notified cases of asbestosis and 121 cases of cancer caused by or suspected as being caused by asbestos. Of these asbestos-induced diseases, 76% were recognized as occupational diseases by insurance institutions. Over half of the cases (64 %) were seen among men over the age of 65, the oldest being over 90.
Most asbestos-induced diseases were notified in the manufacture of motor vehicles and other transport equipment, and the construction sector. Exposure to asbestos was previously common in these sectors. The number of asbestosis cases today is only half of their highest value in the mid-90s, whereas the numbers of lung cancer and mesothelioma cases show an almost flat trend.
Follow-up of asbestos-exposed workers in Finland
The follow-up of asbestos exposed-workers is based on Government Regulation 1485/2001. Detailed instructions for doctors are given by FIOH. During their period of employment, workers undergo periodical health examinations, conducted by occupational health services.
Retired workers are advised to contact their municipal health centre or family doctor. Usually triennial health examinations include a clinical examination, lung function test (spirometry) and chest radiograph.
Diagnosing asbestos-related diseases (ARDs)
Most ARDs are diagnosed in FIOH’s clinics and the occupational medicine outpatient clinics of University Hospitals, which is where patients are referred by physicians from occupational and municipal health centres.According to the law, any medical doctor who encounters a new case of confirmed or suspected occupational disease must notify this to the regional Occupational Safety and Health Inspectorate without delay.
Both employers and physicians must send their respective certificates concerning new cases of compensable occupational diseases to insurance companies, whose own physicians then decide whether or not to recognize a compensation claim.
Accurate assessment of exposure is important, especially in compensable cases, when the insurance company decides whether the patient’s lung cancer should be recognized as an occupational disease. This applies not only to ARDs but also to other occupational diseases.
FIOH has proposed screening of lung cancer among asbestos-exposed workers (FIOH, 2011), based on increasing evidence that the screening of high-risk groups for lung cancer, using low-dose computed tomography, can reduce mortality from lung cancer and all causes.