Radiological abnormalities and asbestos exposure among custodians of the New York City Board of Education.

Six hundred sixty custodians employed by the New York City Board of Education underwent examination from 1985 through 1987 for asbestos-related disease and other general medical conditions by the clinical staff of the Division of Environmental and Occupational Medicine of the Mount Sinai School of Medicine of the City University of New York. Two-thirds of the men (no women were examined) were 20 or more years from onset of any custodial work, with 44% having had at least 20 years of employment as custodial workers in New York City Board of Education schools. Twenty-four percent had begun custodial work in buildings 30 or more years earlier. Findings among them were of particular interest since asbestos-related disease might forecast what might be expected among school custodians with less seniority. Since the Board of Education, in selecting custodians for examination, had chosen only custodians currently employed, the study group comprised men still working in the school system. These, then, represented a "survivor population" (4% had retired between the time of enrollment in the study and the date of examination, and only one of the seventeen retirees had left work owing to disability). Although a considerable amount of clinical information was obtained, abnormalities on chest X-ray consistent with asbestos-induced scarring were used as the key index of disease resulting from exposure to asbestos. Since scarring of the lung tissue or lining of the lung or chest wall (pleura) may be present but undetectable on standard chest radiographs (a relatively insensitive diagnostic technique), the prevalence of abnormality on X-ray film represents a conservative estimate of the actual burden of scarring lung disease in the group. Such changes are indicative of previous asbestos exposure, however, and provide evidence of an increased risk of later asbestos-related malignancy. Overall, abnormalities on chest X-ray consistent with asbestos-related scarring were found in 28% of the men examined. The expected relationship of increasing prevalence of radiographic changes with increasing time since onset of exposure in buildings was demonstrated; among those with 35 or more years since beginning custodial work, 39% had abnormal films. This is evidence that custodial workers as a group have had asbestos exposure in the past, as reflected also in the work histories obtained at the time of examination. Eighty-four percent reported that they themselves removed asbestos-containing materials in the course of their work. Eighty-nine percent had been present in the work area during asbestos abatement projects in the schools in more recent years.(ABSTRACT TRUNCATED AT 400 WORDS)