Asbestos-related disease in Bangladeshi ship breakers: a pilot study

Our plain-English summary of Asbestos-related disease in Bangladeshi ship breakers: a pilot study, by M.N. Courtice, P.A. Demers, T.K. Takaro, et al (International Journal of Occupational and Environmental Health, 2011).

The study

• Authors: M.N. Courtice, P.A. Demers, T.K. Takaro, S. Vedal, S.K. Ahmad, H.W. Davies, Z. Siddique
• Journal: International Journal of Occupational and Environmental Health
• Published: 2011;17(2):144-53
• Cited by: 8 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

A pilot study tested the feasibility of conducting occupational health research in Bangladesh while examining prevalence of asbestos-related diseases including asbestosis, work-related respiratory symptoms, and attitudes to occupational health and safety among a group of internal migrant ship breakers. Data was collected on clinical and work history, respiratory symptoms, and occupational health and safety practices in Bengali. A B-reader read all postero-anterior chest x-rays. In the 104 male ship breakers studied, prevalence of asbestos-related disease was 12%, of which asbestosis accounted for 6%. Knowledge of asbestos and occupational health and safety measures were almost nonexistent. The prevalence of asbestos-related diseases is low compared to studies in shipbuilders and repairers, but a risk underestimate could have resulted from challenges identified during study design and implementation including: industry noncooperation and a culture of corruption; technological and language barriers; and a regional lack of physician knowledge and research on occupational diseases.

In plain English

This pilot study tested whether occupational health research was feasible in Bangladesh and looked for asbestos-related disease among 104 male ship breakers. They were internal migrant workers seen in their home villages in a northwest district. Each had started ship-breaking work at least 10 years earlier, and all were assumed to have been exposed to asbestos. A physician interviewed and examined them, and one certified B-reader scored their chest x-rays. Twelve workers (12%) had asbestos-related findings: six cases of asbestosis (five possible, one probable; 6%) and six pleural abnormalities, five of them pleural plaques. All cases were in beach-based workers. Only six ship-based workers took part. None of the odds ratios linking disease to job type, years worked or years since first employment was statistically significant. Most workers (87%) did not know what the word asbestos meant, and none had ever used a respirator. The authors concluded that, although asbestosis prevalence was lower than expected, they could not conclude that it was low among Bangladeshi ship breakers. They named as limitations a single x-ray reader, non-random recruitment, no exposure measurements and poor x-ray quality.

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: Pilot study testing feasibility and methods: interviews (including American Thoracic Society respiratory questions), physical examination, and chest x-rays scored by one NIOSH-certified B-reader using ILO guidelines
• Who was studied: 104 male ship breakers who were internal migrant workers, studied in their home villages in a northwest district of Bangladesh. They had worked on the ship-breaking yards for at least one year, starting at least 10 years earlier. Participation rate was 88% (104 of 118 invited). 94% were beach-based workers and 6% were ship-based workers.
• Exposure: Asbestos from dismantled ships, assumed for all subjects; no fiber type was named and no exposure measurements were taken. Employment served as a proxy for exposure: job type (beach-based vs ship-based), duration of employment, and years since first employment.
• Main results:
  • Asbestosis: five possible and one probable case among the 104 workers, grouped as six cases (prevalence 6%)
  • Pleural abnormalities in six workers: five pleural plaques and one costophrenic angle obliteration. These brought all asbestos-related disease to 12 cases.
  • None of the pleural abnormalities occurred in workers with asbestosis, and all were in beach-based workers. Asbestosis was found in five loaders and one cable puller, all with under eight years of exposure.
  • Workers employed 3 to 7 years had about six times the odds of asbestosis of those employed under 3 years (odds ratio 5.6, 95% CI 0.9 to 35.1, adjusted for age and smoking). No odds ratio was statistically significant.
  • Among the 104 workers, 37% reported any respiratory symptom; 13% had work-related cough and phlegm and 8% work-related shortness of breath, all in beach-based workers
  • 87% of workers did not know what was meant by asbestos. Although 69% reported using some form of protective equipment, nobody interviewed had ever used a respirator.
• The authors' conclusion: The authors concluded that asbestosis prevalence (6%) was lower than they expected, but that they could not conclude the prevalence among ship breakers in Bangladesh was low. They also concluded that workers' knowledge of asbestos was almost nonexistent.
• Limitations the authors state:
  • Only one B-reader assessed the x-rays, which the authors said could bias the main outcome
  • The asbestosis case definition included some round opacities, so prevalence could have been overestimated
  • Recruitment was not random. Any available listed ship breaker was accepted, and ship-based workers (presumed more highly exposed) were under-represented.
  • There was no exposure assessment to check assumptions about which jobs were more exposed
  • Poor x-ray technique could have affected the reading of the films
  • Interview answers were prone to inaccuracy: subjects had trouble recalling their age, and some copied other villagers' responses

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis, Pleural plaques and thickening, Shipyards and maritime work.

Medical terms in this study, explained in our Lexicon: Work History, B-Reader, Chest X-Ray, Occupational Disease.

Related studies

• Parenchymal asbestosis due to primary asbestos exposure among ship-breaking workers: report of the first cases from Bangladesh — V. Muralidhar, M.F. Ahasan, et al. (2017)
• Radiological evidence of asbestos disease among ship repair workers — I.J. Selikoff, W.J. Nicholson, et al. (1980)
• Assessment of the future mesothelioma disease burden from past exposure to asbestos in ship recycling yards in India — R. Singh, J.W. Cherrie, et al. (2020)
• Asbestos related abnormalities among United States merchant marine seamen — P.J. Barrett (1990)
• Clinical value of fluorodeoxyglucose-positron emission tomography/computed tomography in differentiation of malignant mesothelioma from asbestos-related benign pleural disease: an observational pilot study — H. Yildirim, M. Metintas, et al. (2009)
• Radiographic search for asbestos-related disease in a naval shipyard — J.S. Felton (1979)

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