Asbestos-related disease in public school custodians

Our plain-English summary of Asbestos-related disease in public school custodians, by L.C. Oliver, N.L. Sprince, R. Greene (American Journal of Industrial Medicine, 1991).

The study

• Authors: L.C. Oliver, N.L. Sprince, R. Greene
• Journal: American Journal of Industrial Medicine
• Published: 1991;19(3):303-16
• Cited by: 18 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. 004101).

Abstract

A cross-sectional prevalence study of 120 public school custodians was carried out. The purposes were 1) to investigate the prevalence of asbestos-related disease in a group of custodians at risk for asbestos exposure in public schools and 2) to determine the proportion with disease attributable to exposures in school buildings. Medical and occupational histories, flow-volume loops, and posterior-anterior, lateral, and anterior oblique (AO) chest radiographs were obtained. Single breath DLCO was measured and chest auscultation performed. Mean age of subjects was 57 years and mean duration of work as a custodian, 27 years. Fifty-seven (47.5%) had no known or likely exposure to asbestos outside of their work as a school custodian (NOE). Pleural plaques (PP) occurred in 40 (33%) of the total group and 12 (21%) of the group with NOE. Pulmonary restriction (FVC less than 80% predicted, FEV1/FVC% greater than or equal to 70) occurred in 22 (18%) of the total group and 10 (17%) of those with NOE. DLCO was lower in the group with restriction. Multivariate analysis revealed significant associations (p less than 0.05) between both PP and restriction and duration of asbestos exposure. AO radiographs increased PP detection by a factor of 1.9. Our results reveal PP prevalence in excess of background and pulmonary restriction in the study population, and indicate that PP are attributable to asbestos in schools. Findings with regard to pulmonary restriction need further investigation. Prudent management of asbestos in buildings is indicated for the prevention of related disease.

In plain English

This cross-sectional study examined Boston public school custodians in 1987 and 1988. After one exclusion, 120 white men, active and retired, were analyzed. They gave work and medical histories and had breathing tests and four-view chest X-rays. Fifty-seven men (47.5%) reported no asbestos exposure outside their school custodial work. Pleural plaques appeared in 40 men (33.3%) overall and in 12 (21%) of the 57 without outside exposure, and plaques were significantly more common in men with outside exposure. Lung restriction was found in 22 men (18.3%) overall and in 10 (17.5%) without outside exposure. Both plaques and restriction were statistically associated with duration of asbestos exposure. In 50 re-read film sets, adding oblique X-ray views increased plaque detection by a factor of 1.9. One participant later developed malignant mesothelioma. He had also worked six months in a naval shipyard. The authors concluded that the plaques were attributable to asbestos exposure in schools, and that the findings suggested hidden lung scarring linked to custodial work. They noted that participation was voluntary and that no unexposed comparison group was available.

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: cross-sectional morbidity (prevalence) study
• Who was studied: Active or retired members of the Boston Public School Custodians Association, examined in 1987 (52) and 1988 (69). 120 white males were analyzed after one man was excluded for amiodarone use. 102 of 197 eligible active custodians (51.8%) took part, plus 18 retired custodians. Mean age was 56.9 years.
• Exposure: Work as custodians in Boston public school buildings with friable asbestos-containing material. Tasks included sweeping and dusting plaster or insulation dust, patching or removing torn pipe and boiler insulation, and boiler maintenance. 57 men reported no outside exposure. Outside exposures were mostly from shipbuilding and repair or building construction. Mean time employed as a custodian was 26.1 years.
• Main results:
  • Pleural plaques were found in 40 of 120 custodians (33.3%).
  • Among the 57 custodians with no outside asbestos exposure, 12 (21%) had pleural plaques. Plaques were significantly more common in those with outside exposure (28 of 63, 44.4%; p = 0.007).
  • For the whole group, controlling for smoking, pleural plaques were significantly associated with duration of asbestos exposure (p = 0.0265) and with latency (p = 0.0146).
  • In the group with no outside exposure, pleural plaques were associated with duration of work as a school custodian (p = 0.0155) and with latency (p = 0.0163).
  • A restrictive lung defect was found in 18% of the study population (22 men) and in 10 (17.5%) of the group with no outside exposure.
  • Controlling for cigarette smoking, restriction was positively associated with duration of asbestos exposure in the total group (p = 0.0044) and in the group with no outside exposure (p = 0.0420).
  • Diffusing capacity (DLCO, percent predicted) was lower in men with restriction (78.5 vs 88.9, p = 0.0108).
  • In 50 re-read film sets, 19 showed plaques on four views compared with 10 on front and side views only (38% vs 20%), a factor of 1.9.
  • Three subjects (2.5%) had small irregular opacities of profusion 1/0. All three reported outside asbestos exposure.
  • In multivariate analysis, dyspnea was associated with duration of asbestos exposure (p = 0.0346).
  • One participant later developed malignant mesothelioma. He had worked 32 years as a school custodian and 6 months as a sheetmetal worker in a naval shipyard in 1942, and his chest radiograph showed plaques.
• The authors' conclusion: The authors concluded that pleural plaque prevalence was in excess of background, that the plaques were attributable to asbestos exposure in schools, and that the findings suggested hidden (occult) interstitial fibrosis associated with work as a custodian. They also described the significance of the restriction finding as unclear.
• Limitations the authors state:
  • Participation was voluntary, which can introduce selection bias.
  • No external unexposed comparison group was available, and no internal low-exposure group could be identified.
  • Custodians may have been misclassified as to whether they had asbestos exposure outside school work.
  • Because custodians moved often between schools, the group without outside exposure could not be classified by level of asbestos exposure.

Topics

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

Medical terms in this study, explained in our Lexicon: Asbestos Exposure, Chest X-Ray, Diffusing Capacity (DLCO), Pleural Plaques, FEV1/FVC Ratio, Multivariate Analysis.

Related studies

• Asbestos-related abnormalities in school maintenance personnel — L.C. Oliver, N.L. Sprince, et al. (1991)
• A radiographic survey of public school building maintenance and custodial employees — H.A. Anderson, L.P. Hanrahan, et al. (1992)
• Asbestos-related disease in custodial and building maintenance workers from a large municipal school district — J.R. Balmes, A. Daponte, et al. (1991)
• Radiological abnormalities and asbestos exposure among custodians of the New York City Board of Education — S.M. Levin, I.J. Selikoff (1991)
• Tribal Odisha Eye Disease Study Report # 6. Opportunistic screening of vitamin A deficiency through School Sight Program in tribal Odisha (India) — L. Panda, S. Nayak, et al. (2020)
• Asbestos in New York City public school buildings--public policy: is there a scientific basis? — R. Wilson, A.M. Langer, et al. (1994)

Browse more research in American Journal of Industrial Medicine, or return to medical research.