Screening for asbestos-induced diseases in Finland

Our plain-English summary of Screening for asbestos-induced diseases in Finland, by K. Koskinen, J.P. Rinne, A. Zitting, et al (American Journal of Industrial Medicine, 1996).

The study

• Authors: K. Koskinen, J.P. Rinne, A. Zitting, A. Tossavainen, J. Kivekäs, K. Reijula, P. Roto, M.S. Huuskonen
• Journal: American Journal of Industrial Medicine
• Published: 1996;30(3):241-51
• Cited by: 30 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Screening for asbestos-induced diseases in Finland was carried out in 1990-1992 as a part of the Asbestos Program of the Finnish Institute of Occupational Health. The aim of the present study was to find the workers who had developed an asbestos-induced disease in certain occupations. Examination of active or retired workers included a personal interview on work history and asbestos exposure, and a chest X-ray. The target group for the screening comprised workers under 70 years of age who had worked at least for 10 years in construction, 1 year in a shipyard or in the manufacture of asbestos products. A preliminary questionnaire was sent to 54,409 workers, 18,943 of whom finally participated in the screening examination. The mean age of the workers was 53 years; 95% were employed in construction, 2% in shipyards, and 3% in the asbestos industry. The criteria for a positive screening result were (1) a radiographic finding clearly indicating lung fibrosis (at least ILO category 1/1), (2) a radiographic finding indicating mild lung fibrosis (ILO category 1/0) with unilateral or bilateral pleural plaques, (3) marked abnormalities of the visceral pleura (marked adhesions with or without pleural thickening), or (4) bilateral pleural plaques. The positive cases totalled 4,133 (22%) and were sent for further investigation. In addition to the screening, information on the presence of asbestos in the work environment, prevention of asbestos exposure, as well as on the health effects of asbestos exposure and smoking were given to the participating workers. The screening acted as a preliminary survey to prompt further national follow-up of asbestos-induced diseases among the workers who have been exposed to asbestos. This article presents the material, methods, and overall results of the screening.

In plain English

This article described a chest X-ray screening program run in Finland in 1990-1992 by the Finnish Institute of Occupational Health. The screening targeted workers under 70 who had worked at least 10 years in construction, or at least 1 year in a shipyard or in asbestos product manufacturing. A preliminary questionnaire, which also asked about exposure time, went to 54,409 workers; 24,589 were invited and 18,943 were examined. Each person had an interview about work history, asbestos exposure and smoking, and chest X-rays. Those examined were 96% men, with a mean age of 53 and a mean 26 years in the risk occupation. Most had worked in construction. In total, 4,133 (22%) were screening-positive and were sent for further examination. Bilateral pleural plaques were found in 17%, adherences and thickening of the visceral pleura in 7%, and lung fibrosis in 3%. Positive results were more common in older age groups. The authors concluded that most of the recorded X-ray changes were caused by asbestos. They noted that X-rays were not double-read and miss some plaques.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Cross-sectional screening study using a questionnaire, a personal interview and chest X-rays. The article reports the material, methods and overall results of the screening.
• Who was studied: Screening held in Finland in 1990-1992. The target group was workers under 70 years of age with qualifying work in construction, shipyards or the asbestos product industry. A preliminary questionnaire was sent to 54,409 workers and 36,308 responded. Of the 24,589 invited, 18,943 were examined. Participants were 96% men, with a mean age of 53 years, and 65% of the men were active workers. Most worked in construction (17,937), with 456 from shipbuilding and 550 from the asbestos industry.
• Exposure: Occupational asbestos exposure in construction (at least 10 years), shipyards (at least 1 year) or the asbestos product industry (at least 1 year). Exposure level and duration were assessed from the questionnaire answers, and 1,657 people were treated as not exposed or as having low exposure. The mean working time in the risk occupation was 26 years. The article does not report fiber measurements for the study group. In its discussion it notes that anthophyllite asbestos was widely used in Finland.
• Main results:
  • Among the 18,943 people examined, 4,133 (22%) were screening-positive, with suspected or verified occupational disease.
  • Among those examined, 17% had bilateral pleural plaques, 7% had adherences and thickening of the visceral pleura, and 3% had lung fibrosis.
  • The percentage of screening-positive cases was higher in the older age groups.
  • The largest occupational groups among those screened were carpenters (25%), electricians (12%) and plumbers (12%).
  • Participation among those invited was 77% in construction (17,937 of 23,338), 87% in shipbuilding (456 of 522) and 75% in the asbestos industry (550 of 729).
  • In a test set of 100 radiographs read by all seven radiologists, 70-88% of present-or-absent classifications agreed on average between any two readings.
  • Among 100 screening-positive subjects examined by high-resolution CT, 20 had X-ray lung opacities of ILO profusion 1/1 or higher. Of these 20, 12 had signs of fibrosis on CT, 2 had suspected fibrosis, and 7 had emphysema. The CT scans showed plaques better than the X-rays did.
• The authors' conclusion: The authors concluded that the target group was selected with rigorous criteria, so almost all invited persons had significant asbestos exposure and most of the classified X-ray changes were caused by asbestos. They also considered the response rate high enough for the results to be well representative of the target group.
• Limitations the authors state:
  • Radiographs were not double-read, for economic reasons.
  • Only part of pleural plaques show on X-rays, so the authors stated that a considerably greater proportion of those examined had plaques than the results indicate.
  • Nearly one third of those contacted did not reply, and older workers were more often unwilling to attend the examination.
  • Clinical examinations and lung function tests were left out at the initial stage because of their expense.
  • The screening was not designed to find asbestos-induced cancers.
  • Municipal and state construction workers were not included.
  • Within the LEL pension fund group, the authors could not exclude workers who had worked mostly in land-and-water construction.

Mines named here

Asbestos mines this study is about. Each mine's page says who ran it, when it worked, and what it produced.

• Paakkila mine, Finland

All asbestos mines

Topics

Medical terms in this study, explained in our Lexicon: Work History, Asbestos Exposure, Chest X-Ray, Fibrosis, Bilateral, Pleural Plaques, Visceral Pleura, Pleural Thickening.

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