Pulmonary Function in Granite Dust Exposure A Four Year Follow Up

Our plain-English summary of Pulmonary Function in Granite Dust Exposure A Four Year Follow Up, by A.W. Musk, J.M. Peters, D.H. Wegman, et al (1977).

The study

• Authors: A.W. Musk, J.M. Peters, D.H. Wegman, L.J. Fine
• Published: American Review of Respiratory Disease, Volume 115. February 10th 1977
• Type of article: Journal article
• Our copy: from Johns-Manville's own medical library. The article is still under copyright, so we describe it here rather than post it.

In plain English

This prospective study followed men in Vermont granite sheds, who were exposed to granite dust. In 1970, 1,216 actively employed men had lung function tests, and testing was repeated yearly. Of these, 668 men were followed for 4 years in jobs whose dust exposure had not changed. Workers were grouped as high or low exposure using dust measurements made in 1970. Yearly decline was 0.07 to 0.08 liter for forced vital capacity (FVC) and 0.05 to 0.07 liter for forced expiratory volume in one second (FEV1). The authors called this excessive compared with healthy groups in other studies, which declined by less than 40 ml per year. At 2 years the high-exposure group showed somewhat larger yearly declines than the low-exposure group, which the authors called suggestive. At 4 years, no clear difference between the exposure groups was shown. Smoking increased the decline, but the authors said smoking alone could not explain it. The authors concluded that present dust levels in the sheds cause excessive loss of lung capacity and must be lowered. They had no unexposed comparison group.

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: Prospective (longitudinal) study of lung function, with repeated yearly testing of a working cohort, compared against published data from other populations
• Who was studied: Men actively employed in Vermont granite sheds: 1,216 in the 1970 cohort. 828 were analysed over 2 years and 668 over 4 years (1970 to 1974), in jobs whose exposure had not changed. An additional 528 workers had changes measured over 1, 2 or 3 years. In 1974, 974 workers were tested in total.
• Exposure: Granite dust (granite and quartz dust measured in 1970). Occupations were graded into high and low exposure by their mean 1970 dust concentration. Cutters, carvers, sculptors and polishers formed the high-exposure group.
• Main results:
  • Among the 668 workers followed for 4 years, the yearly decline was 0.07 to 0.08 liter per year for FVC and 0.05 to 0.07 liter per year for FEV1, which the authors described as excessive
  • Healthy control series from other studies showed yearly declines in FEV1 and FVC of less than 40 ml
  • The excessive decline was consistent regardless of the length of follow-up, including in the additional 528 workers followed for 1, 2 or 3 years
  • Over 2 years (1970 to 1972), the yearly decline was 51 ml for FEV1 and 60 ml for FVC. Yearly FEV1 decline was 0.059 liter in the high-exposure group versus 0.046 liter in the low-exposure group. The authors described this as a suggestive relationship with exposure.
  • After 4 years, the authors could no longer show a difference between exposure groups. Yearly declines were FEV1 0.054 liter in the high-exposure group (279 workers) versus 0.052 liter in the low-exposure group (389 workers), and FVC 0.081 liter in both.
  • The decline in FEV1 and FVC was lowest in never-smokers, intermediate in ex-smokers and highest in current smokers; analysis of variance showed the smoking effect was significant
  • In nonsmokers, the 4-year FEV1 decline was not different from predicted, but the FVC decline was excessive
• The authors' conclusion: The authors concluded that present dust concentrations in Vermont granite sheds cause excessive deterioration of lung capacity, that this was due to occupation rather than smoking alone, and that dust concentrations must be lowered
• Limitations the authors state:
  • No unexposed control group could be studied, because practically all workers in the granite industry are exposed; comparisons relied on outside populations
  • Exposure was assigned from a single occupational mean concentration measured in 1970. These means did not accurately reflect any one person's exposure, and exposure ranges overlapped between high and low groups. The authors considered this the likely reason no dose-response relationship appeared at 4 years.
  • Loss of subjects from the cohort may have affected the results
  • The authors did not know whether the 4-year changes could be projected over a whole working life in the industry

Topics

Medical terms in this study, explained in our Lexicon: FEV1.

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