Roentgenographic evidence for predominant left-sided location of unilateral pleural plaques

Our plain-English summary of Roentgenographic evidence for predominant left-sided location of unilateral pleural plaques, by B.F. Withers, A.M. Ducatman, W.N. Yang (Chest, 1989).

The study

• Authors: B.F. Withers, A.M. Ducatman, W.N. Yang
• Journal: Chest
• Published: 1989;95(6):1262-4
• Cited by: 16 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. 000179).

Abstract

The roentgenographic prevalence and anatomic distribution of pleural plaques were studied in the US Navy Asbestos Medical Surveillance Program population (105,064 individuals as of July 17, 1985). "Definite" or "probable" pleural plaques were noted in 4.4 percent of films. These were unilateral in 19.3 percent of roentgenograms with "definite" pleural plaque and 33.9 percent of films with "probable" pleural plaque. Unilateral findings were more often left-sided than right-sided; a ratio of 287:82 in the "definite" group and 625:287 in the "probable" group. Left-sided predominance of unilateral plaque is a consistent and unexplained epidemiologic finding that may provide clues to pleural pathogenesis following asbestos exposure.

In plain English

This study examined chest X-rays from the US Navy Asbestos Medical Surveillance Program. X-rays of 105,064 civilian and military Navy employees, taken from 1978 to 1985, were each read by one of 23 independent experts, who recorded whether pleural plaques were "possible," "probable," or "definite" and on which side. Overall, 4.4 percent of the X-rays showed "definite" or "probable" plaques. Among 45,854 workers with age data, the share with plaques rose from 0.33 percent at age 24 or under to 15.27 percent at 55 and over. It also rose with years of employment. Plaques were on one side only in 19.3 percent of "definite" and 33.9 percent of "probable" readings. One-sided plaques were more often on the left: 287 left versus 82 right among "definite" readings, and 625 versus 287 among "probable" readings. The authors called this left-sided predominance consistent but unexplained, and possibly a clue to how plaques form after asbestos exposure. They noted that X-rays both miss plaques and falsely show them, and that a reading bias favoring the left side could not be ruled out.

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: Radiographic survey (cross-sectional analysis) of chest X-rays from an asbestos medical surveillance program. Each film was read once by one of 23 ILO-qualified readers, and the most recent film per person from 1978 to 1985 was used.
• Who was studied: 105,064 civilian and military employees of the US Navy in the Navy Asbestos Medical Surveillance Program, with X-rays read from 1978 to 1985. Age and years-of-service data were available for 45,854 of them.
• Exposure: Membership in the US Navy asbestos medical surveillance program. The article does not give fiber types, products, specific jobs or exposure levels. Length of Navy employment was used for the subgroup with demographic data.
• Main results:
  • Of all 105,064 X-rays, 4.4 percent showed "definite" or "probable" pleural plaque.
  • In the 45,854 workers with demographic data, 5.00 percent (2,294) had "definite" or "probable" plaque. The proportion rose with age, from 0.33 percent (21 of 6,301) at 24 or younger to 15.27 percent (968 of 6,340) at 55 and over. It also rose with length of employment, from 1.09 percent (0 to 10 years) to 15.57 percent (31 or more years).
  • Plaques were on one side only in 44.7 percent of "possible," 33.9 percent of "probable," and 19.3 percent of "definite" plaque readings.
  • One-sided plaques were more often on the left than the right. The counts were 287 left to 82 right in the "definite" group and 625 left to 287 right in the "probable" group. The left-to-right ratio grew with reader certainty, reaching 3.5 to 1 for "certain" readings.
  • The authors noted a 0.33 percent plaque rate in the youngest workers. They said this does not fit the latency expected for a workplace-related finding.
• The authors' conclusion: The authors concluded that left-sided predominance of one-sided plaques is a consistent but unexplained finding. They said it could reflect greater susceptibility, larger size or earlier appearance of left-sided plaques, or greater visibility on the left. They said it may give clues to how plaques form after asbestos exposure.
• Limitations the authors state:
  • Chest X-rays detect pleural plaque with uncertain accuracy. Plaques are often missed, and plaques are falsely assigned to some people, notably the obese.
  • A prevalence figure from a working population underestimates eventual plaque occurrence. Reasons include detection difficulty, long latency, exclusion of retired workers, and inclusion of recently employed or lightly exposed workers.
  • The authors could not rule out that something about ILO interpretation favors perceiving plaques on the left.
  • Older, more experienced, or more affected workers may have entered the program ahead of others. Demographic data were available for only part of the population.
  • The higher share of one-sided plaques among less certain readings could reflect reader reluctance to give more certain ratings to one-sided plaque.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Pleural plaques and thickening.

Medical terms in this study, explained in our Lexicon: Pleural Plaques, Asbestos Exposure.

Related studies

• The left-sided predominance of asbestos-related pleural disease — H. Hu, L. Beckett, et al. (1993)
• Absence of left-sided predominance in asbestos-related pleural plaques: a CT study — J.C. Gallego (1998)
• Intensity-modulated radiation therapy with simultaneous integrated boost in unresected left-sided pleural mesothelioma: a case report — S. Cilla, C. Digesú, et al. (2010)
• Roentgenographic manifestations and pulmonary function effects of asbestos-induced pleural thickening — L. Rosenstock (1991)
• Roentgenographic evidence of asbestos exposure in a select population of railroad workers — M.J. Sepulveda, J.A. Merchant (1983)
• Smoking and roentgenographic opacities in US Navy asbestos workers — A.M. Ducatman, B.F. Withers, et al. (1990)

Browse more research in Chest, or return to medical research.