Asbestos-dust exposures at various levels and mortality

Our plain-English summary of Asbestos-dust exposures at various levels and mortality, by P.E. Enterline, M.A. Kendrick (Archives of Environmental Health, 1967).

The study

• Authors: P.E. Enterline, M.A. Kendrick
• Journal: Archives of Environmental Health
• Published: 1967;15(2):181-6
• Cited by: 64 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 001478).

In plain English

This study tracked deaths through June 30, 1963 among 21,755 white men aged 15 to 64 who worked in US asbestos products plants between 1948 and 1951. They came from 15 building products, 11 friction materials and 9 asbestos textile plants. 6,281 cotton textile workers served for comparison. Historical dust data proved inadequate, but the authors judged dust lowest in building products plants and highest in asbestos textile plants. Deaths were compared with US white male death rates, where a ratio of 100 means the expected number. Overall mortality was raised only among asbestos textile workers (120.6), who had excess respiratory cancer (228.6), digestive cancer and asbestosis. Building products and friction materials workers had overall ratios (88.5 and 88.8) close to cotton workers (88.2), but raised respiratory cancer ratios (130.4 and 123.7). The cohort had 44 deaths from asbestosis as underlying cause under age 65 and 50 asbestosis deaths at all ages. The comparable figure was 160 among US white males of all ages in 1950 to 1962. The authors concluded that asbestos dust at general-population levels probably is of little importance in causing disease. Follow-up lasted at most 16 and a half years.

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 mortality study comparing observed deaths with numbers expected from US white male death rates (standardized mortality ratios), with cotton textile workers as a comparison group
• Who was studied: 21,755 white men aged 15 to 64 who worked in US asbestos products plants at some time during 1948 through 1951: 12,402 in asbestos building products, 7,510 in asbestos friction materials and 1,843 in asbestos textile products. A further 6,281 cotton textile workers were included as controls. Workers were identified from social security tax records, and deaths were followed through June 30, 1963.
• Exposure: Asbestos dust in asbestos building products, friction materials and textile products plants. Fiber types were not specified. No usable dust measurements existed. Based on impressions from plant surveys, exposure was judged lowest in building products plants, higher in friction materials plants and heaviest in asbestos textile plants, with none in cotton textile plants.
• Main results:
  • Standardized mortality ratios for all causes of death were 88.5 for asbestos building products workers, 88.8 for friction materials workers, 120.6 for asbestos textile workers and 88.2 for cotton textile workers. An elevated all-cause death rate was found only in the asbestos textile group.
  • Standardized mortality ratios for cancer of the respiratory system were 130.4 for building products workers, 123.7 for friction materials workers and 228.6 for asbestos textile workers. Cotton textile workers had a ratio of 31.1, based on fewer than 10 deaths.
  • 63 workers in the asbestos products cohort died with asbestosis listed as an underlying or contributory cause. By industry this was 10 building products workers (0.81 per 1,000), 29 friction materials workers (3.86 per 1,000) and 24 asbestos textile workers (13.02 per 1,000). No cotton textile workers died with asbestosis mentioned.
  • The asbestos products cohort had 44 deaths with asbestosis listed as the underlying cause at ages under 65, and 50 asbestosis deaths at all ages. The total recorded among all US white males at all ages from 1950 to 1962 was 160.
  • Among asbestos textile workers, the excess mortality was attributed to cancer of the respiratory system, cancer of the digestive system (ratio 146.3), a heart disease category that includes cor pulmonale (ratio 176.5), and asbestosis.
  • Among asbestos building products workers, the excess of respiratory disease deaths was not due only to asbestosis. The authors suggested that other respiratory disease hazards likely exist in that industry.
  • The term mesothelioma appeared on only one of the 1,853 death certificates examined, for a worker in the asbestos building products industry.
• The authors' conclusion: The authors concluded that health hazards from asbestos dust were concentrated mainly in the asbestos textile industry. They judged that exposures in the building products and friction materials industries greatly exceeded those in modern urban communities. In their view, the modest response in those industries indicates that asbestos dust at general-population levels probably is of little importance in causing disease.
• Limitations the authors state:
  • Follow-up lasted at most 16 and a half years, and the authors noted that longer follow-up might show more striking health effects.
  • The duration of exposure could not be defined. Some workers had long prior employment, and many left the industry soon after entering the cohort.
  • Historical dust-level data were inadequate, so the plan to link measured dust levels to mortality was abandoned.
  • Death certificates could not be found for 229 of the 2,082 reported deaths. These deaths were assumed to follow the same cause distribution as the located certificates, and the authors did not know whether this introduced bias.
  • Diagnostic practices may have differed from place to place, which could affect comparisons with national expected numbers.
  • Exposure varied considerably within plants, and small groups in the lower-exposure industries may have been as intensely exposed as asbestos textile workers.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestos textiles, Asbestosis.

Related studies

• Exposures and mortality among chrysotile asbestos workers. Part I: exposure estimates — J.M. Dement, R.L. Harris, et al. (1983)
• Exposures and mortality among chrysotile asbestos workers. Part II: mortality — J.M. Dement, R.L. Harris, et al. (1983)
• Dust exposure and mortality in an American chrysotile textile plant — A.D. McDonald, J.S. Fry, et al. (1983)
• Dust exposure and mortality in an American factory using chrysotile, amosite, and crocidolite in mainly textile manufacture — A.D. McDonald, J.S. Fry, et al. (1983)
• Increased mortality in COPD among construction workers exposed to inorganic dust — I.A. Bergdahl, K. Torén, et al. (2004)
• Lung cancer mortality in North Carolina and South Carolina chrysotile asbestos textile workers — L. Elliott, D. Loomis, et al. (2012)

Browse more research in Archives of Environmental Health, or return to medical research.