Association of mesothelioma deaths with neighborhood asbestos exposure due to a large-scale asbestos-cement plant

Our plain-English summary of Association of mesothelioma deaths with neighborhood asbestos exposure due to a large-scale asbestos-cement plant, by Y. Kitamura, L. Zha, R. Liu, et al (Cancer Science, 2023).

The study

• Authors: Y. Kitamura, L. Zha, R. Liu, M. Shima, T. Nakaya, N. Kurumatani, S. Kumagai, J. Goji, T. Sobue
• Journal: Cancer Science
• Published: 2023;114(7):2973-2985
• Cited by: 5 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

A causal relationship between mesothelioma and occupational asbestos exposure is well known, while some studies have shown a relationship to non-occupational exposures. The aim of this study was to quantify the risk of mesothelioma death associated with neighborhood asbestos exposure due to a large-scale asbestos-cement (AC) plant in Amagasaki, Japan, adjusting properly risk factors including occupational exposures. We conducted a nested case-control study in which a fixed population of 143,929 residents who had been living in Amagasaki City between 1975 and 2002 were followed from 2002 to 2015. All 133 cases and 403 matched controls were interviewed about their occupational, domestic, household, and neighborhood asbestos exposures. Odds ratios (ORs) for mesothelioma death associated with the neighborhood exposure were estimated by a conditional logistic-regression model. For quantitative assessments for neighborhood exposure, we adopted cumulative indices for individuals' residential histories at each residence-specific asbestos concentration multiplied by the duration during the potential exposure period of 1957-1975 (crocidolite). We observed an increasing, dose-dependent risk of mesothelioma death associated with neighborhood exposure, demonstrating that ORs in the highest quintile category were 21.4 (95% confidence interval [CI] 5.8-79.2) for all, 23.7 (95% CI 3.8-147.2) for males, and 26.0 (95% CI 2.8-237.5) for females compared to the lowest quintile, respectively. A quantitative assessment for risk of mesothelioma deaths, adjusting for occupational and non-occupational exposures separately, showed a dose-dependent association with neighborhood exposure and no substantial gender differences in magnitude.

© 2023 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.

In plain English

This nested case-control study examined mesothelioma deaths among long-term residents of Amagasaki City, Japan, the site of a large asbestos-cement plant that used crocidolite. The cohort was 143,929 residents aged 40 or older who had lived in the city since before 1975. They were followed from 2002 to 2015. Interviews covered 133 people who died of mesothelioma, mostly answered by a spouse or child, and 403 matched controls, mostly answered by the controls themselves. After people who had directly handled asbestos were excluded, 101 cases and 342 controls were analyzed. Neighborhood exposure was estimated from each person's addresses during 1957 to 1975, by multiplying modeled asbestos concentrations by the years lived there. Compared with the lowest fifth of exposure, the highest fifth had odds ratios of 23.7 (95% CI 3.8 to 147.2) in males and 26.0 (2.8 to 237.5) in females. Among people rated as having no occupational exposure, the highest-level figure was 6.86 (1.24 to 37.82). The authors concluded that the association was dose-dependent, with no substantial gender difference. They noted that occupational confounding may not have been fully removed, that response rates were low, and that causes of death were not histologically verified.

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: Nested (population-based) case-control study within a long-term resident cohort, analyzed with conditional logistic regression
• Who was studied: Cohort of 143,929 residents of Amagasaki City, Japan, aged 40 or more, who had lived in the city continuously from before 1975 until at least 2002. They were followed from 2002 to 2015. The cases were 133 mesothelioma deaths (pleural and peritoneal), and there were 403 controls matched by sex and age. After people who had directly handled asbestos were excluded, 101 cases and 342 controls were analyzed.
• Exposure: Neighborhood exposure to airborne asbestos from a large asbestos-cement plant during 1957 to 1975, when crocidolite was used there. It was measured as a cumulative index: the simulated relative asbestos concentration at each residence multiplied by the years lived there (year/m3). Occupational, domestic and household exposures were adjusted for.
• Main results:
  • Highest versus lowest quintile of cumulative neighborhood exposure: odds ratio 23.7 (95% CI 3.8 to 147.2) for males and 26.0 (95% CI 2.8 to 237.5) for females
  • The odds ratios showed a statistically significant increasing trend with level of neighborhood exposure, P for trend less than 0.001, in both males and females
  • For males and females combined, the odds ratio for the highest neighborhood exposure level was 21.4 (95% CI 5.8 to 79.2)
  • When the analysis was limited to people whose occupational exposure was rated 'none' (45 cases, 249 controls), odds ratios for levels 2, 3, 4 and 5 versus level 1 were 0.69 (0.05 to 9.41), 1.03 (0.16 to 6.47), 3.71 (0.74 to 18.60) and 6.86 (1.24 to 37.82)
  • Median distance of residences from the plant was 1645.1 m for cases and 2880.5 m for controls
• The authors' conclusion: The authors concluded that, after adjusting for occupational and non-occupational exposures, neighborhood exposure showed a dose-dependent association with mesothelioma death, with no substantial gender differences in magnitude.
• Limitations the authors state:
  • Respondents differed: for cases they were mostly spouses or children, while for controls they were mostly the subjects themselves
  • Response rates were low: 56.6% for cases and 9.7% for contacted controls
  • Mesothelioma deaths came from death certificates without histological verification
  • The two-step approach may not have fully controlled confounding from occupational exposure
  • Asbestos fibers that fell to the ground after emission were not considered, nor were daily-living exposures near the plant. The exposure period also excluded 1975 to 1995, when the plant used other asbestos types.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma.

Medical terms in this study, explained in our Lexicon: Mesothelioma, Asbestos Exposure, Asbestos-Cement, Non-Occupational Exposure, Occupational Exposure, nested case-control study, Odds Ratio, Environmental Exposure.

Related studies

• Asbestos fiber concentration in the area surrounding a former asbestos cement plant and excess mesothelioma deaths in residents — S. Kumagai, N. Kurumatani (2009)
• The relationship between malignant mesothelioma and an asbestos cement plant environmental risk: a spatial case-control study in the city of Bari (Italy) — M. Musti, A. Pollice, et al. (2009)
• Identification of novel candidate oncogenes and tumor suppressors in malignant pleural mesothelioma using large-scale transcriptional profiling — G.J. Gordon, G.N. Rockwell, et al. (2005)
• Cyclin Pathway Genomic Alterations Across 190,247 Solid Tumors: Leveraging Large-Scale Data to Inform Therapeutic Directions — D.L. Jardim, S.Z. Millis, et al. (2021)
• Large-scale copy number analysis reveals variations in genes not previously associated with malignant pleural mesothelioma — M. Hylebos, G. Van Camp, et al. (2017)
• Retrospective analysis of large-scale research screening of construction workers for the early diagnosis of mesothelioma — T. Hirohashi, K. Igarashi, et al. (2014)

Browse more research in Cancer Science, or return to medical research.