Asbestos and tuberculosis in Trieste, Italy

Our plain-English summary of Asbestos and tuberculosis in Trieste, Italy, by A.M. Walker, G. Stanta, M. Delendi (Journal of Occupational Medicine., 1985).

The study

• Authors: A.M. Walker, G. Stanta, M. Delendi
• Journal: Journal of Occupational Medicine.
• Published: 1985;27(11):831-4
• Cited by: 1 article, 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. 001244).

Abstract

The distribution of counts of asbestos bodies in lung specimens from 25 persons dying of fibrocaseous tuberculosis was essentially identical to that in age- and sex-matched control subjects. Although tuberculosis mortality has been elevated in the past in cohorts of asbestos workers, asbestos exposure at environmental levels found in a region with a history of heavy asbestos use appears to be unassociated with risk of tuberculosis. Potentiation of the risk of death from tuberculosis may require both a high risk of tuberculosis in the general community and intense personal exposure to asbestos.

In plain English

This matched case-control study used autopsy lung tissue from the province of Trieste, Italy, a region with a history of heavy asbestos use. The cases were 25 adults who died of pulmonary tuberculosis between 1977 and 1982. Each had two controls, matched for age and sex, who died in the same year of causes other than tuberculosis and unrelated to asbestos. The researchers counted asbestos bodies per gram of lung tissue; the authors say these bodies mainly reflect amphibole exposure. The mean square-root count was 2.25 in tuberculosis cases and 2.77 in controls. The matched analysis gave a two-sided p value of 0.6, unchanged after adjusting for place of residence. Separately, the authors pooled published data from four earlier cohorts of asbestos workers. Those cohorts had 85 tuberculosis deaths and an overall standardized mortality ratio of 156 (95% confidence interval 125 to 194), though some were miners possibly also exposed to silica. The authors concluded that environmental-level asbestos exposure appeared unassociated with tuberculosis risk. They suggested that a raised risk of tuberculosis death may require both a high community tuberculosis risk and intense personal asbestos exposure.

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: Matched case-control study using autopsy lung specimens. Each tuberculosis decedent was matched to two controls by age, sex and availability of lung tissue. The authors also pooled tuberculosis mortality data from previously published cohorts of asbestos workers.
• Who was studied: 25 adults who died of pulmonary (fibrocaseous) tuberculosis in the province of Trieste, Italy, between 1 January 1977 and 31 December 1982, and 50 matched controls who died of other causes.
• Exposure: Environmental (non-occupational) asbestos exposure in Trieste, measured as asbestos bodies per gram of wet lung tissue in paraffin-embedded autopsy samples. The authors state that asbestos bodies mainly reflect amphibole asbestos exposure. Fiber types were not identified in this study.
• Main results:
  • A method check on two autopsies, comparing paraffin-embedded with formalin-fixed adjacent samples, showed excellent agreement between the asbestos body counts.
  • Asbestos body counts were highly skewed, with no apparent systematic difference between tuberculosis cases and controls.
  • The mean square-root asbestos body count was 2.25 in tuberculosis cases and 2.77 in controls.
  • The matched analysis on the square-root counts gave a two-sided p value of 0.6. Further adjustment for place of residence left this value unchanged.
  • Testing interactions of asbestos body counts with age and sex did not suggest any subgroup at high risk.
  • The time tuberculosis patients spent in rural sanitoria was judged unlikely to have seriously affected their asbestos body counts.
  • Pooling previously published data from four cohorts of asbestos workers (fiber type listed as chrysotile in the authors' table), the authors found an overall standardized mortality ratio for tuberculosis of 156, based on 85 observed deaths, with a 95% confidence interval of 125 to 194.
• The authors' conclusion: The authors concluded that asbestos exposure at the environmental levels found in a region with heavy past asbestos use appears to be unassociated with tuberculosis risk. They suggested that an increased risk of tuberculosis death may require both a high community tuberculosis risk and intense personal asbestos exposure.
• Limitations the authors state:
  • For the pooled cohort data, the authors note that the Quebec and Italian cohorts were miners, who may also have had some silica dust exposure.

Topics

Medical terms in this study, explained in our Lexicon: Asbestos Bodies, Asbestos Exposure.

Related studies

• Asbestosis and tuberculosis — F. Segarra-Obiol, P. Lopez-Ibañez, et al. (1983)
• Pleural mesothelioma in patient with pulmonary tuberculosis: report of a case — U.J. Martinis, V.R. Radovic (1965)
• Evaluation of ALS assay of TB-SA for diagnosis of pulmonary tuberculosis — J. Jiao, M.S. Wang, et al. (2015)
• Malignant mesothelioma of the pleura in Trieste, Italy — L. Giarelli, C. Bianchi, et al. (1992)
• Rounded atelectasis of the lung — G.T. Stathopoulos, M.T. Karamessini, et al. (2005)
• Diffuse pleural mesothelioma in Trieste. A survey based on autopsy cases — C. Bianchi, G. Grandi, et al. (1978)

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