Municipal pleural cancer mortality in Spain

Our plain-English summary of Municipal pleural cancer mortality in Spain, by G. López-Abente, V. Hernández-Barrera, M. Pollán, et al (Occupational and Environmental Medicine, 2005).

The study

• Authors: G. López-Abente, V. Hernández-Barrera, M. Pollán, N. Aragonés, B. Pérez-Gómez
• Journal: Occupational and Environmental Medicine
• Published: 2005;62(3):195-9
• Cited by: 24 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: Pleural cancer is a recognised indicator of exposure to asbestos and mesothelioma mortality.

Aims: To investigate the distribution of municipal mortality due to this tumour, using the autoregressive spatial model proposed by Besag, York, and Mollie.

Methods: It was possible to compile and ascertain the posterior distribution of relative risk on the basis of a single Bayesian spatial model covering all of Spain's 8077 municipal areas. Maps were plotted depicting standardised mortality ratios, smoothed relative risk (RR) estimates, and the distribution of the posterior probability that RR >1.

Results: There was a higher risk of death due to pleural cancer in well defined towns and areas, many of which correspond to municipalities where asbestos using industries once existed for many years, the prime example being the municipal pattern registered for Barcelona Province. The quality of mortality data, the suitability of the model used, and the usefulness of municipal atlases for environmental surveillance are discussed.

In plain English

This study mapped deaths from pleural cancer, coded on death certificates as malignant neoplasm of pleura, in all 8,077 municipalities of Spain from 1989 to 1998. It used a statistical model that smooths random variation by taking neighbouring towns into account. There were 1,647 such deaths, registered in only 601 towns. Raw town-by-town ratios showed no clear pattern. The smoothed map showed higher risk in well-defined towns and areas, many of them places where shipyards or other asbestos-using industries existed for many years, such as El Ferrol, Cartagena, Cadiz, Avilés and Santander. Barcelona Province showed a pattern found nowhere else. Cerdanyola del Valles had the highest relative risk in Spain: 15 deaths observed against 1.49 expected, with a smoothed relative risk of 5.80 (credibility interval 3.24 to 9.57). The authors suggested that the fibre-cement industry possibly accounts for the Barcelona excess. They concluded that the method could pinpoint areas with past asbestos-using industry. They noted that pleural tumours are certified less accurately than other cancers, and that smoothing can wrongly raise or hide a town's risk.

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: Geographic (small-area) study of mortality, using a Bayesian spatial model (the Besag, York and Mollié model) to estimate smoothed relative risks for each municipality
• Who was studied: Deaths from pleural cancer (ICD-9 code 163) in Spain, 1989–98, by town of residence: 1647 deaths in total across all 8077 municipalities, with cases in only 601 towns and cities
• Exposure: Exposure was not measured for individuals. The study compared death rates by place of residence, and the authors related areas of high risk to towns where asbestos-using industries, such as shipyards and fibre-cement plants, existed for many years.
• Main results:
  • The unsmoothed standardised mortality ratio map showed no clearly discernible pattern, mainly separating towns with cases from towns without them
  • The smoothed map highlighted towns where shipyards or other asbestos-using industry existed for many years, including El Ferrol, Cartagena, Cadiz, Avilés and Santander
  • Cerdanyola del Valles (Barcelona Province) had the highest relative risk in Spain: 15 deaths observed vs 1.49 expected, standardised mortality ratio 10.05, smoothed relative risk 5.80 (credibility interval 3.24–9.57)
  • The city of Barcelona: 165 deaths observed vs 79.82 expected, standardised mortality ratio 2.07, smoothed relative risk 2.06 (credibility interval 1.77–2.38)
  • Cadiz: 19 deaths observed vs 5.24 expected, standardised mortality ratio 3.63, smoothed relative risk 3.22 (credibility interval 1.91–4.85)
  • Ferrol: 9 deaths observed vs 3.86 expected, standardised mortality ratio 2.33, smoothed relative risk 2.01, with a credibility interval of 0.92–3.51 that includes 1 (posterior probability of excess risk 0.96)
  • The authors suggested that the fibre-cement industry possibly accounts for the excess in Barcelona Province and in Getafe (south of the Madrid Region)
• The authors' conclusion: The authors concluded that, despite the possible limitations of these recently adopted techniques, the results were able to pinpoint areas that had industrial facilities using asbestos, and that municipal maps may be useful for environmental surveillance
• Limitations the authors state:
  • Death certification of pleural tumours in Spain is less accurate than for other cancer sites
  • Certification problems would mean risk was underestimated in some towns
  • Smoothing can make towns without excess risk appear to have it because their neighbours do (false positives)
  • Smoothing can also hide excess risk in small towns (false negatives)
  • Because of long latency, the pattern reflects exposures from decades earlier

Topics

Medical terms in this study, explained in our Lexicon: Mesothelioma, Relative Risk.

Related studies

• Industrial pollution and pleural cancer mortality in Spain — G. López-Abente, P. Fernández-Navarro, et al. (2012)
• Pleural cancer mortality in Spain: time-trends and updating of predictions up to 2020 — G. López-Abente, M. García-Gómez, et al. (2013)
• Occupational exposures and risk of oesophageal cancer by histological type: a case-control study in eastern Spain — M. Santibañez, J. Vioque, et al. (2008)
• Occupation and risk of malignant pleural mesothelioma: A case-control study in Spain — A. Agudo, C.A. González, et al. (2000)
• Exposure to non-arsenic pesticides is associated with lymphoma among farmers in Spain — E. van Balen, R. Font, et al. (2006)
• Human exposure to trace elements and PCDD/Fs around a hazardous waste landfill in Catalonia (Spain) — M. Herrero, J. Rovira, et al. (2020)

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