Colorectal cancer in asbestos cement workers in Denmark

Our plain-English summary of Colorectal cancer in asbestos cement workers in Denmark, by E. Raffn, E. Villadsen, E. Lynge (American Journal of Industrial Medicine, 1996).

The study

• Authors: E. Raffn, E. Villadsen, E. Lynge
• Journal: American Journal of Industrial Medicine
• Published: 1996;30(3):267-72
• Cited by: 12 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Recent data on the risk of colorectal cancer following exposure to chrysotile are conflicting. We report on colorectal cancer morbidity in a large cohort of asbestos cement workers from Denmark mainly exposed to chrysotile. The total cohort had an SIR of 1.23 (95% CI 1.01-1.48). With a latency period of 15 years, men employed in the early (1928-1950) production period had an SIR of 1.47 (95% CI 1.05-2.01). With the observation of excess risks of colorectal cancer morbidity among chrysotile exposed asbestos cement workers in both Sweden and Denmark the question on the role of chrysotile in the etiology of colorectal cancer remains open.

In plain English

This Danish study followed 8,463 people (7,887 men and 576 women) who worked between 1928 and 1984 at Dansk Eternit-Fabrik A/S, an asbestos cement factory. It compared their colorectal cancer cases from 1943 to 1990 with rates for the Danish population. The factory mainly used chrysotile. Amosite was introduced in 1946, and small amounts of crocidolite were used from 1952 to 1968. The whole cohort had 109 colorectal cancers against 88.93 expected (SIR 1.23; 95% CI 1.01-1.48), which the authors called a borderline statistically significant excess. Because 102 of the cases were in men, the further analysis covered men only. Counting from 15 years after first employment, men first employed in 1928 to 1950 had an SIR of 1.47 (95% CI 1.05-2.01). Among 98 men recorded as cement workers in 1928 to 1941, the SIR was 2.07 (95% CI 0.89-4.07). The authors stressed that this estimate rests on very small numbers. Job titles were otherwise not available. The authors concluded that the Danish and Swedish data point to a 50% excess risk of colorectal cancer in chrysotile-based asbestos cement manufacture. They concluded that the possible role of chrysotile remains open.

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: Cohort study of cancer incidence (morbidity). Observed cases were compared with expected numbers based on Danish population incidence rates (standardized incidence ratios). Follow-up ran to the end of 1990.
• Who was studied: 8,463 people included in the analysis: 7,887 men and 576 women employed between 1928 and 1984 at Dansk Eternit-Fabrik A/S, Denmark. The colorectal analyses beyond the total cohort were restricted to men.
• Exposure: Work in asbestos cement manufacture. Mainly chrysotile; amosite from 1946 and small amounts of crocidolite between 1952 and 1968. Exposure was estimated at 50 to 800 f/ml in 1948 and 10 to 100 f/ml in 1957. Some workers were also exposed to cement.
• Main results:
  • Total cohort, colorectal cancer: 109 observed, 88.93 expected, SIR 1.23 (95% CI 1.01-1.48), described by the authors as borderline statistically significant.
  • Total cohort, rectal cancer: SIR 1.40 (95% CI 1.06-1.82). Right-side colon: SIR 1.11 (95% CI 0.69-1.70). Left-side colon: SIR 1.11 (95% CI 0.74-1.60).
  • Men, 15 years or more since first employment: 79 observed, 61.30 expected, SIR 1.29, 95% CI 1.03-1.61 in the text (Table III prints 1.02-1.61).
  • Men first employed 1928-1950, 15 years or more since first employment: SIR 1.47 (95% CI 1.05-2.01). Table III shows 39 observed and 26.53 expected.
  • Men employed 1928-1941, by job title: 98 cement workers had an SIR of 2.07 (8 cases, 95% CI 0.89-4.07). 269 asbestos workers had an SIR of 1.01 (10 cases, 95% CI 0.48-1.86). 63 maintenance workers had an SIR of 0.92 (2 cases, 95% CI 0.10-3.33).
  • Lung cancer among the workers employed 1928-1950: SIR 1.63 (95% CI 1.26-2.08).
  • All cancers: 857 cases among men, SIR 1.22 (95% CI 1.14-1.30). 48 cases among women, SIR 0.95 (95% CI 0.72-1.26).
• The authors' conclusion: The authors concluded that both the Danish and the Swedish cancer morbidity data point to a 50% excess risk of colorectal cancer among workers making chrysotile-based asbestos cement products. They concluded that the possible role of chrysotile in causing colorectal cancer remains open.
• Limitations the authors state:
  • Job titles were not available in the personnel files. They could only be inferred from employment numbers for 1928-1941.
  • Cement workers may occasionally have also worked in the asbestos cement area.
  • The excess risk seen in the cement workers is based on very small numbers.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Chrysotile, Colon cancer.

Medical terms in this study, explained in our Lexicon: Colorectal Cancer, Asbestos-Cement, Chrysotile, Latency, Etiology.

Related studies

• Lung cancer in asbestos cement workers in Denmark — E. Raffn, E. Villadsen, et al. (1996)
• Incidence of lung cancer by histological type among asbestos cement workers in Denmark — E. Raffn, E. Lynge, et al. (1993)
• Workplace exposure to diesel and gasoline engine exhausts and the risk of colorectal cancer in Canadian men — L. Kachuri, P.J. Villeneuve, et al. (2016)
• Colorectal cancer and asbestos exposure-an overview — Q. Huang, Y.J. Lan (2020)
• Mortality and cancer incidence among Lithuanian cement producing workers — G. Smailyte, J. Kurtinaitis, et al. (2004)
• Incidence of cancer and mortality among employees in the asbestos cement industry in Denmark — E. Raffn, E. Lynge, et al. (1989)

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