An epidemiologic study of a group of talc workers

Our plain-English summary of An epidemiologic study of a group of talc workers, by J.F. Gamble, W. Fellner, M.J. Dimeo (The American Review of Respiratory Disease, 1979).

The study

• Authors: J.F. Gamble, W. Fellner, M.J. Dimeo
• Journal: The American Review of Respiratory Disease
• Published: 1979;119(5):741-53
• Cited by: 25 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. 001025).

Abstract

Chest roentgenograms, pulmonary function assessment by spirometry, respiratory symptoms, smoking history, and occupational history by questionnaire were obtained from 121 male talc miners and millers exposed to talc containing tremolite and anthophyllite asbestiform fibers. Ninety-three of the employees had worked in talc only at the plant under study. Symptoms were only slightly more prevalent in talc workers when compared to potash miners. Mean pulmonary function (forced expiratory volume in one sec, forced vital capacity, and maximal expiratory flow at 50 and 75 per cent of vital capacity) of talc workers was significantly decreased in comparison to that of potash miners. The prevalence of pleural calcification and pneumoconiosis in talc workers with 15 or more years of employment was higher than in potash miners. The prevalence of pleural thickening was 31 per cent in those who worked more than 15 years and was significantly increased as compared to that in potash miners. Workers with pleural thickening had decreased pulmonary function in comparison to those who did not. Decreased one-sec forced expiratory volume and forced vital capacity were associated with exposure to respirable particulate and asbestiform fibers.

In plain English

This cross-sectional study examined 121 of 156 male talc miners and millers in St. Lawrence County, New York. Results were reported for the 93 who had worked only at the study mine and mill. Of the airborne fibers, 38 to 45 per cent were anthophyllite and 12 to 19 per cent tremolite, with small amounts of chrysotile. Workers had chest X-rays, breathing tests and symptom questionnaires. They were compared with 1,077 potash miners, with adjustment for age, height and smoking. Among talc workers employed 15 years or more, 31 per cent had pleural thickening, compared with 4.4 per cent of potash miners. Average FEV1 and FVC (measures of how much air the lungs move) were about 95 per cent of potash workers' values. Workers with higher estimated cumulative dust and fiber exposure had larger deficits. Workers with pleural thickening had lower lung function than those without it. Symptoms were most common in smokers and only slightly more common than in potash miners. The authors concluded that these workers showed increased symptoms, X-ray abnormalities and reduced lung function, some related to dose. They noted that only current workers were studied, the group was small, and exposure estimates were probably too low.

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 study of current workers, compared with a potash miner population
• Who was studied: 121 of 156 male talc millers and miners (78 per cent) at a mine and mill working talc deposits in St. Lawrence County, New York. Results were reported for the 93 who had worked in talc only at this plant. The comparison group was 1,077 potash miners examined by NIOSH.
• Exposure: Talc dust containing asbestiform fibers. In the mine, airborne fibers were 38 per cent anthophyllite, 19 per cent tremolite and 3 per cent chrysotile. In the mill, they were 45 per cent anthophyllite, 12 per cent tremolite and 2 per cent chrysotile. The rest were unidentified. Free silica exposures were low. Cumulative exposure was estimated as fibers per ml times years and as mg per cubic metre times years of respirable particulate.
• Main results:
  • Among talc workers employed 15 years or more, the prevalence of pleural thickening was 31 per cent, 7 times higher than in potash workers (4.4 per cent). The difference was reported as P less than 0.005. Among those employed less than 15 years, rates were 1.6 per cent in talc workers and 0.5 per cent in potash miners.
  • Among all 93 talc workers, the overall prevalence of pleural thickening was 11 per cent, and 24 per cent in those aged 40 or more. There was one case each of rounded opacities, irregular opacities and pleural calcification. There was no pleural calcification in the potash population.
  • After adjustment for age, height, smoking status and years worked, mean FEV1 and FVC in talc workers were about 95 per cent of potash workers' values (94.5 and 94.7 per cent of predicted). Flows at 50 and 75 per cent of FVC were about 85 per cent.
  • Decreased FEV1 and FVC were related to estimated exposure. Per 100 fibers per ml times years, the change in per cent of predicted was minus 13.7 for FEV1 and minus 12.7 for FVC. FEV1/FVC ratio and flow rates were not significantly related to exposure.
  • Compared with talc workers without pleural thickening, mean FEV1 was 11 percentage points lower in those with extent 1 pleural thickening and 15 points lower in those with extent 2. Mean FVC was 10 and 14 points lower, respectively.
  • Among the 93 talc workers, prevalence was 32 per cent for cough, 31 per cent for phlegm, 8 per cent for hemoptysis and 14 per cent for dyspnea of grade 2 or greater. These symptoms were most prevalent in smokers and were only slightly more prevalent than in potash miners.
• The authors' conclusion: The authors concluded that the findings showed increased respiratory symptoms, radiographic abnormalities and decreased pulmonary function among these talc miners and millers, with some findings related to dose and duration of exposure. They said the population should be followed for cause-specific mortality and respiratory morbidity.
• Limitations the authors state:
  • Only presently employed workers were studied (selective survival); there was no information on former workers.
  • The population was small for estimating chronic effects and dose-response, and 22 per cent did not participate.
  • Cumulative exposure was only an index. Little particulate and no fiber sampling was done before 1970, and past exposures were likely higher, so estimates are probably lower than actual exposure.
  • The potash comparison group was not unexposed: those miners had diesel exhaust and potash dust exposure.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Talc and vermiculite.

Medical terms in this study, explained in our Lexicon: Talc, Spirometry, Occupational History, Tremolite, Anthophyllite, Asbestiform, Pleural Calcification, Pneumoconiosis.

Related studies

• Respiratory effects from industrial talc exposure among former mining workers — R.C. Loyola, A.P. Carneiro, et al. (2010)
• Lung function and radiographic change in chrysotile workers in Swaziland — M. McDermott, M.M. Bevan, et al. (1982)
• Lung function 22-35 years after treatment of idiopathic spontaneous pneumothorax with talc poudrage or simple drainage — P. Lange, J. Mortensen, et al. (1988)
• Talc dust pneumoconiosis — A. Berner, B. Gylseth, et al. (1981)
• Evaluation of respiratory effects in miners and millers exposed to talc free of asbestos and silica — D.H. Wegman, J.M. Peters, et al. (1982)
• Decline in annual lung function in workers exposed to asbestos with and without pre-existing fibrotic changes on chest radiography — T. Nakadate (1995)

Browse more research in The American Review of Respiratory Disease, or return to medical research.