Clinical Features, Mortality And Survival Of Patients With Asbestosis

Our plain-English summary of Clinical Features, Mortality And Survival Of Patients With Asbestosis, by M.S. Huuskonen (1978).

The study

• Author: M.S. Huuskonen
• Published: Scandinavian Journal Of Work, Environment And Health 4(4):265-274, December (1978)
• Type of article: Journal article
• Our copy: from Johns-Manville's own medical library, J-M no. 002126. The article is still under copyright, so we describe it here rather than post it.

In plain English

This Finnish study described 202 asbestosis patients diagnosed at the Institute of Occupational Health, among 229 cases reported to the Finnish Register of Occupational Diseases from 1964 to 1976. The author reexamined 133 of the 140 still alive. They included insulation workers, asbestos sprayers, asbestos cement product factory workers and asbestos quarry workers. Of the 133, 118 (88.7%) reported breathlessness and 95 (71.4%) had persistent sputum. Crackling sounds in the chest (crepitations) were heard in 77 (57.9%), and 43 (32.3%) had finger clubbing. Compared with Finnish men of the same ages, 56 men had died against 23.4 expected, including 19 lung cancer deaths against 2.1 expected. No excess was found for other cancers. Among the men, smokers had shorter estimated survival than ex- and nonsmokers combined. The author wrote that the results suggest breathlessness is the most important symptom of asbestosis. Among the 20 who died of lung cancer, the quarry workers had been exposed to anthophyllite and those in other occupations to mixed asbestos, chiefly chrysotile. The author noted that small numbers and mixed exposure made fiber-specific risk hard to judge.

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: Clinical case series of registered asbestosis patients. Survivors were clinically reexamined. Deaths were followed up and compared with the Finnish general male population, and survival was analysed by life tables.
• Who was studied: 202 patients diagnosed with asbestosis at the Institute of Occupational Health, Finland. They came from 229 cases reported to the Finnish Register of Occupational Diseases between 1964 and 1976. 133 surviving patients (113 men, 20 women) were reexamined. The mortality and survival analyses covered men only.
• Exposure: Occupational asbestos exposure among insulation workers, asbestos sprayers, asbestos cement product factory workers, asbestos quarry workers and others. Fiber types were described only for the patients who died of lung cancer. The quarry workers among them had been exposed to anthophyllite. Those in the other occupations had mixed exposure, chiefly chrysotile with smaller amounts of anthophyllite, crocidolite and amosite.
• Main results:
  • Of the 133 reexamined patients, 95 (71.4%) had persistent sputum
  • Of the 95 patients with persistent sputum, 19 (20.0%) were nonsmokers and 36 (37.9%) were exsmokers
  • Of the 133 reexamined patients, 118 (88.7%) reported some kind of breathlessness
  • 77 of the 133 reexamined patients (57.9%) had crepitations in the chest
  • Finger clubbing was present in 43 of the 133 reexamined patients (32.3%)
  • Of the 174 men registered with asbestosis, 56 had died, compared with 23.4 deaths expected among Finnish men of the same age
  • Among the men, 19 lung cancer deaths were observed against 2.1 expected
  • No excess mortality was found among the men for other cancers (other malignomas)
  • Among the men, the risk rate ratio was 9.0 for lung cancer death and 2.4 for overall mortality
  • Of the 62 patients (men and women) who died before 1977, the underlying cause of death was asbestosis in 26 (41.9%) and lung cancer in 20 (32.2%)
  • Only one patient who died of lung cancer was a nonsmoker
  • Among men with asbestosis, life expectancy was shorter for smokers than for non- and exsmokers (analysed as one combined group)
• The authors' conclusion: The author wrote that the results suggest breathlessness is the most important symptom of asbestosis. The author's reason was that the more severe the breathlessness, the greater the decrease in lung function and the more diffuse the fibrosis on X-ray.
• Limitations the authors state:
  • Women were too few and were left out of the mortality and survival analyses
  • Exsmokers and nonsmokers were too few to analyse separately for survival, so the two groups were combined
  • Small case numbers and mixed exposure made it difficult to judge the lung cancer risk from different fiber types
  • The data were too scanty to evaluate the lung cancer risk ratio between smoking and nonsmoking patients

Topics

Medical terms in this study, explained in our Lexicon: Occupational Disease, Insulator, Asbestos-Cement, Sputum, Clubbing, Lung Cancer, Anthophyllite, Chrysotile.

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