Analysing health data from rare occupational cohorts

Our plain-English summary of Analysing health data from rare occupational cohorts, by T.F. Bateson (Occupational and Environmental Medicine, 2014).

The study

• Author: T.F. Bateson
• Journal: Occupational and Environmental Medicine
• Published: 2014;71(11):742-3
• Type of article: Comment
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher

In plain English

This article was a commissioned commentary, not an original study. The author discussed a separate study by Allen et al, in the same journal issue, of deaths among Minnesota taconite mining industry workers, whose exposures included elongated mineral particles, among them amphiboles. As described here, Allen et al started from 68 737 workers at seven Mesabi Iron Range operations. Of 44 213 remaining workers, they excluded 13 176 (nearly 30%) employed less than 1 year. The author argued this practice merits greater scrutiny and that data on short-term workers in a rare cohort could be reported separately. The author noted that Allen et al found lung cancer deaths 1.16 times (95% CI 1.09 to 1.24) and mesothelioma deaths 2.77 times (95% CI 1.87 to 3.96) higher than expected for the Minnesota population. The author wrote that this suggests taconite-related exposures may be risk factors for mesothelioma. Because the ICD-10 mesothelioma code only became available in 1999, earlier deaths were missed, though the author saw no reason this would change Allen et al's interpretation. The author concluded that studies of rare exposures should make the greatest use of available data.

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: Commentary (commissioned, internally peer reviewed) on another study (Allen et al) published in the same issue; not original research
• Who was studied: No population was studied by this author. The commentary discussed Allen et al's cohort of 68 737 workers from seven mining operations in Minnesota's Mesabi Iron Range, of whom 44 213 remained after initial exclusions and 13 176 more were excluded for under 1 year of employment. Mortality follow-up ran from 1960 through 2007.
• Exposure: Exposures related to taconite mining, including elongated mineral particles such as amphiboles. Allen et al described these as non-asbestiform amphibole and non-amphibole elongate mineral particles.
• Main results:
  • The commentary reported that Allen et al excluded nearly 30% of the remaining 44 213 workers (13 176 workers) by restricting to those with at least 1 year of employment. The author argued this practice should merit greater scrutiny.
  • As reported by the commentary, Allen et al found lung cancer mortality among the taconite workers 1.16 times higher than expected in the Minnesota population (95% CI 1.09 to 1.24).
  • As reported by the commentary, Allen et al found mesothelioma mortality among the taconite workers 2.77 times higher than expected in the Minnesota population (95% CI 1.87 to 3.96). The author wrote that this suggests taconite-related exposures may also be risk factors for mesothelioma.
  • The ICD-10 mesothelioma code C45 did not become available until 1999, so mesothelioma deaths before 1999 could not be identified by that code, although follow-up began in 1960. The author saw no reason to think this incomplete ascertainment would change Allen et al's interpretation. The author suggested that, given the rarity of mesothelioma, death certificates could be reviewed to recover earlier deaths, as other investigators had done.
• The authors' conclusion: The author concluded that large studies of rare exposures are uncommon, so authors describing them should make the greatest use of the available data. The author added that the taconite data set may hold further data yet to be described.

Topics

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

Related studies

• Mortality experience among Minnesota taconite mining industry workers — E.M. Allen, B.H. Alexander, et al. (2014)
• The origins of public concern with taconite and human health: Reserve Mining and the asbestos case — M.E. Berndt, W.C. Brice (2008)
• Occupational exposures and lung cancer risk among Minnesota taconite mining workers — E.M. Allen, B.H. Alexander, et al. (2015)
• A case-control study of mesothelioma in Minnesota iron ore (taconite) miners — C.S. Lambert, B.H. Alexander, et al. (2016)
• Comprehensive assessment of exposures to elongate mineral particles in the taconite mining industry — J. Hwang, G. Ramachandran, et al. (2013)
• Risk assessment due to environmental exposures to fibrous particulates associated with taconite ore — R. Wilson, E.E. McConnell, et al. (2008)

Browse more research in Occupational and Environmental Medicine, or return to medical research.