Time trends and occupational risk factors for peritoneal mesothelioma in Sweden

Our plain-English summary of Time trends and occupational risk factors for peritoneal mesothelioma in Sweden, by K. Hemminki, X. Li (Journal of Occupational and Environmental Medicine, 2003).

The study

• Authors: K. Hemminki, X. Li
• Journal: Journal of Occupational and Environmental Medicine
• Published: 2003;45(4):451-5
• Cited by: 17 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Epidemiologic data on peritoneal mesothelioma are scarce but exposure to asbestos is an identified risk factor. To characterize the disease, time trends, age-incidence relationships, and occupational risk factors for peritoneal mesothelioma were studied based on the Swedish Family-Database covering years 1961 to 1998. Peritoneal mesothelioma is a rare disease and only 96 male and 113 female cases were recorded during the 38-year period. Age-standardized incidence of the disease has increased for men until 1985 and leveled off thereafter. The incidence in women has been equally high but it has continued to increase toward the end of the follow-up period. The incidence was maximal at an age around 80 years for both genders. No female occupational or socioeconomic group was at risk. For men, 29% of the cases had typical asbestos related jobs with a SIR of 1.70. Bricklayers and plumbers had the highest risk of 7.22 and 5.12, respectively. Within limits of the sample size, no evidence was noted for risk from environmental exposures to asbestos because the risk of farmers and that of urban residents were not different.

In plain English

The authors studied peritoneal mesothelioma (of the abdominal lining) using a Swedish database linking cancer records from 1961 to 1998 with occupations from the 1960 census. They found 96 male and 113 female cases. Incidence rose in both sexes until 1981 through 1985. After that the male rate stayed around 0.12 per 100,000, while the female rate rose to 0.16 per 100,000 by 1996 to 1998. Incidence peaked around age 80. Of the 96 male cases, 28 (29%) held asbestos-related jobs in 1960. Their standardized incidence ratio (SIR) was 1.70 (95% CI 1.13 to 2.47). Bricklayers (4 cases, SIR 7.22, 95% CI 1.88 to 18.66) and plumbers (4 cases, SIR 5.12, 95% CI 1.33 to 13.24) ranked highest. No female occupational or socioeconomic group differed significantly from all women. Male farmers had an SIR of 0.76 (95% CI 0.36 to 1.40); from this and city-versus-countryside comparisons, the authors reported that environmental exposures did not show significant effects. The authors concluded that their data, though limited in statistical power, suggest that most asbestos-related male cases came from use of asbestos-containing products.

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: Registry-based incidence study using the Swedish Family-Cancer Database, with standardized incidence ratios (SIRs) by occupation, socioeconomic group and region
• Who was studied: 96 male and 113 female peritoneal mesothelioma cases recorded in Sweden from 1961 to 1998. They were drawn from a database of all persons born in Sweden after 1931 with their parents (over 10.2 million individuals).
• Exposure: Occupation and socioeconomic group recorded in the 1960 census. Asbestos-related occupations were defined in advance as mechanics, plumbers, welders, electricians, painters, bricklayers and other construction workers. Fiber types were not studied.
• Main results:
  • Incidence rose in both sexes up to 1981 through 1985. After that the male rate stayed constant and the female rate continued to increase.
  • Among men, incidence remained around 0.12 per 100,000 after 1985. Female incidence reached 0.16 per 100,000 by 1996 to 1998.
  • Male and female age-specific rates were similar. Both peaked around age 80, with some indication of an early age component at 55 to 64 years.
  • Men in asbestos-related occupations had 28 cases and an SIR of 1.70 (95% CI 1.13 to 2.47). These 28 were 29% of the 96 male cases.
  • Male bricklayers had 4 cases and an SIR of 7.22 (95% CI 1.88 to 18.66). Male plumbers had 4 cases and an SIR of 5.12 (95% CI 1.33 to 13.24).
  • Male farmers (agriculture) had 10 cases and an SIR of 0.76 (95% CI 0.36 to 1.40).
  • The authors reported that environmental exposures did not show significant effects. This rested on two indirect comparisons: the farmers' SIR was only marginally below 1, and large-city incidence was not raised beyond what urban asbestos-related jobs would explain.
  • No female group differed significantly from all women. Female mechanics had an SIR of 6.71 from two cases, with a wide 95% CI of 0.63 to 24.68.
  • By region, the only significant difference was an SIR of 1.33 (64 cases, 95% CI 1.02 to 1.70) for women in southern Sweden. Men in the three large cities had an SIR of 1.22 (39 cases, 95% CI 0.87 to 1.67).
• The authors' conclusion: The authors concluded that their data, though limited in statistical power, suggest that most asbestos-related male cases of peritoneal mesothelioma are due to use of asbestos-containing products (the 'second wave' of asbestos disease). They suggested the increase in women may be related to nonoccupational exposure or to reasons other than asbestos.
• Limitations the authors state:
  • The authors could not assess whether mesothelioma was underreported in the past. They also noted that some ovarian tumors are difficult to distinguish from mesothelioma.
  • Occupation was recorded only in 1960, so the share of male cases ever employed in asbestos-related industries was probably larger than 29%.
  • The small number of cases limited the statistical power of the data.

Topics

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

Medical terms in this study, explained in our Lexicon: Peritoneal Mesothelioma, Environmental Exposure.

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