Lung function among asbestos cement factory workers: cross-sectional and longitudinal study

Our plain-English summary of Lung function among asbestos cement factory workers: cross-sectional and longitudinal study, by A. Siracusa, C. Cicioni, R. Volpi, et al (American Journal of Industrial Medicine, 1984).

The study

• Authors: A. Siracusa, C. Cicioni, R. Volpi, P. Canalicchi, G. Brugnami, A.R. Comodi, G. Abbritti
• Journal: American Journal of Industrial Medicine
• Published: 1984;5(4):315-25
• Cited by: 27 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 000576).

Abstract

Ventilatory capacity tests and standardized respiratory questionnaires were used in 1973 and in 1980 to measure the effect of mixed dust exposure in the asbestos cement industry on respiratory symptoms and lung function in 65 exposed workers and 30 controls (exposed to polyvinyl chloride but not to asbestos). Workers exposed to asbestos had 1) a higher prevalence of breathlessness and chest pain, and a higher incidence of breathlessness; 2) lower 1980 values of forced vital capacity (FVC) (0.27-0.83 liters) and forced expiratory volume in 1 sec (FEV1) (0.23-0.62 liters); and 3) a faster decline (nearly 40 ml/year) in FVC and FEV1 between 1973 and 1980. The FVC annual decrease was 52.5 ml in the subjects with more than 15 years since first asbestos exposure, whereas it was 24.3 ml in those with less than 15 years, suggesting a faster decline after 15 years of exposure. The effect of asbestos exposure and smoking habits was less than additive as regards pulmonary function.

In plain English

At a factory making building products from asbestos cement and polyvinyl chloride (PVC), breathing tests and questionnaires in 1973 and 1980 compared 65 asbestos cement workers (asbestos mainly chrysotile, some crocidolite) with 30 controls exposed to PVC but not asbestos. After adjusting for age and smoking, breathlessness and chest pain were significantly more common among asbestos workers. In 1980, asbestos workers had lower forced vital capacity (FVC, by 0.27 to 0.83 liters) and FEV1 (by 0.23 to 0.62 liters) than PVC workers. Both measures declined faster, by nearly 40 ml per year. Among asbestos workers, FVC fell 52.5 ml a year in those more than 15 years past first exposure, against 24.3 ml in those with less. The combined effect of asbestos and smoking on lung function was less than additive. The authors concluded that heavy asbestos exposure is associated with excessive loss of breathing capacity, apparently appearing only 10 to 15 years after first exposure. They noted that asbestos fiber levels could not be measured in 1980, after production ended, and that symptoms may have been over-reported.

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 and longitudinal (follow-up) study with surveys in 1973 and 1980, using respiratory questionnaires and spirometry
• Who was studied: Workers at a factory making PVC and asbestos cement building products. Of 111 subjects studied in 1973, follow-up data were obtained in 1980 on 65 asbestos-exposed workers and 30 PVC-exposed controls. The 1980 cross-sectional analysis covered 51 PVC workers, 57 asbestos low-exposure workers and 19 asbestos high-exposure workers. The authors were based in Perugia and Gubbio, Italy.
• Exposure: Mixed dust in asbestos cement manufacture: asbestos (mainly chrysotile and a small amount of crocidolite) at 15-20%, blended with portland cement. Mixing and grinding areas were defined as high exposure and all other asbestos cement areas as low exposure. Controls were exposed to PVC dust. Total dust measured in 1973 in the asbestos cement mixing area was more than four times the 3 mg/m3 maximum admissible concentration cited by the authors. Asbestos cement production ended in December 1978.
• Main results:
  • After adjustment for age and smoking habits, breathlessness grade 2 or more and chest pain were significantly more frequent in asbestos-exposed subjects than in PVC-exposed subjects (p less than 0.05)
  • In 1980, FVC and FEV1 expressed as percentage of predicted were significantly lower in asbestos high-exposure subjects than in the PVC and asbestos low-exposure groups
  • Compared with PVC workers, asbestos workers had lower 1980 FVC (0.27-0.83 liters) and FEV1 (0.23-0.62 liters)
  • After adjustment for smoking, the yearly decline in FVC and FEV1 between 1973 and 1980 was higher in the asbestos group than in the PVC group (p less than 0.05), by nearly 40 ml per year
  • Among the 57 subjects without breathlessness in 1973, the mean annual incidence of breathlessness from 1973 to 1980 was 1.2% in the PVC group and 6.0% in the asbestos group
  • Within the asbestos group, the 12 subjects with less than 15 years since first asbestos exposure had annual declines of 24.3 ml (FVC) and 37.6 ml (FEV1). The 53 subjects with more than 15 years had annual declines of 52.5 ml (FVC) and 50.9 ml (FEV1).
  • On lung function, the authors found an additive effect of smoking with PVC dust exposure but a less than additive effect of smoking with asbestos exposure
• The authors' conclusion: The authors concluded that heavy exposure to asbestos is associated with an excessive loss of ventilatory capacity that is not further increased by simultaneous cigarette smoking. They also concluded that this excessive loss seems to appear only after 10-15 years from first asbestos exposure.
• Limitations the authors state:
  • Asbestos fiber concentrations could not be measured in 1980 because asbestos cement production had ended in December 1978
  • The 1973 survey, carried out by another medical team, had only one forced expiratory spirogram per subject
  • The high frequency of breathlessness and chest pain may be partly due to excess reporting, because workers were aware of the harmful effects of asbestos

Topics

Medical terms in this study, explained in our Lexicon: Asbestos-Cement, FEV1, Asbestos Exposure, Habit.

Related studies

• Decreased lung function in long-term asbestos cement workers: a cross-sectional study — C.G. Ohlson, T. Rydman, et al. (1984)
• Lung function and respiratory symptoms in subjects with asbestos-related disorders: a cross-sectional study — B. Hilt, J.T. Lien, et al. (1987)
• Are the knowledge of non-malignant asbestos-related diseases and lung function impairment differentially associated with psychological well-being? A cross-sectional study in formerly asbestos-exposed workers in Germany — J. Lang, M.K. Felten, et al. (2019)
• Longitudinal changes in pulmonary function of asbestos workers — X. Wang, M. Wang, et al. (2010)
• Dust levels in an asbestos-cement factory: problem solving — A. Sharon (1986)
• Asbestos-related disease in railroad workers. A cross-sectional study — L.C. Oliver, E.A. Eisen, et al. (1985)

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