Cumulative exposure to dust causes accelerated decline in lung function in tunnel workers

• Published in: Occupational and environmental medicine (London, England) Vol. 58; no. 10; pp. 663 - 669
• Main Authors: Ulvestad, B, Bakke, B, Eduard, W, Kongerud, J, Lund, M B
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd 01.10.2001; BMJ Publishing Group; BMJ; BMJ Publishing Group LTD; BMJ Group
• Subjects: Adult; Aerosols; Asthma; Asthma - diagnosis; Asthma - etiology; Biological and medical sciences; Case-Control Studies; Cellulose acetate; Chemical and industrial products toxicology. Toxic occupational diseases; Concrete construction; Confined Spaces; Construction industry; Dioxides; Dust; Dust - adverse effects; Employees; Engineering; Forced Expiratory Volume; Gases; Healthy Worker Effect; Heavy construction; Humans; Inorganic dusts (pneumoconiosises) and organic dusts (byssinosis etc.); Logistic Models; Longitudinal Studies; Lung Diseases - etiology; lung function; Lungs; Maximal Midexpiratory Flow Rate; Medical sciences; Middle Aged; Mineral Oil - adverse effects; Mist; Nitrogen; Nitrogen dioxide; Nitrogen Dioxide - adverse effects; Occupational exposure; Occupational Exposure - adverse effects; Odds Ratio; Pore size; Quartz; Quartz - adverse effects; Radioallergosorbent Test; Radiography; respirable dust; Respiratory function; Respiratory symptoms; Risk factors; Silicosis; Silicosis - diagnostic imaging; Silicosis - etiology; Smoking - adverse effects; Statistics, Nonparametric; Tobacco smoking; Toxicology; Tunnels; Underground construction; Vital Capacity; Workers; United Kingdom > UK; Ann Arbor Michigan; United States > US; Human; Respiratory disease; Toxicity; Cumulated dose; Occupational exposure; Quartz; Epidemiology; Construction industry; Gases; Dust; Lung function; Underground construction; Professional activity; Occupational medicine; Public health; Tunnels
• ISSN: 1351-0711; 1470-7926
• DOI: 10.1136/oem.58.10.663

OBJECTIVES To examine whether underground construction workers exposed to tunnelling pollutants over a follow up period of 8 years have an increased risk of decline in lung function and respiratory symptoms compared with reference subjects working outside the tunnel atmosphere, and relate the findings to job groups and cumulative exposure to dust and gases. METHODS 96 Tunnel workers and a reference group of 249 other heavy construction workers were examined in 1991 and re-examined in 1999. Exposure measurements were carried out to estimate personal cumulative exposure to total dust, respirable dust, α-quartz, oil mist, and nitrogen dioxide. The subjects answered a questionnaire on respiratory symptoms and smoking habits, performed spirometry, and had chest radiographs taken. Radiological signs of silicosis were evaluated (International Labour Organisation (ILO) classification). Atopy was determined by a multiple radioallergosorbent test (RAST). RESULTS The mean exposure to respirable dust and α-quartz in tunnel workers varied from 1.2–3.6 mg/m3 (respirable dust) and 0.019–0.044 mg/m3 (α-quartz) depending on job task performed. Decrease in forced expiratory volume in 1 second (FEV1) was associated with cumulative exposure to respirable dust (p<0.001) and α-quartz (p=0.02). The multiple regression model predicted that in a worker 40 years of age, the annual decrease in FEV1 would be 25 ml in a non-exposed non-smoker, 35 ml in a non-exposed smoker, and 50–63 ml in a non-smoking tunnel worker (depending on job). Compared with the reference group the odds ratio for the occurrence of new respiratory symptoms during the follow up period was increased in the tunnel workers and associated with cumulative exposure to respirable dust. CONCLUSIONS Cumulative exposures to respirable dust and α-quartz are the most important risk factors for airflow limitation in underground heavy construction workers, and cumulative exposure to respirable dust is the most important risk factor for respiratory symptoms. The finding of accelerated decline in lung function in tunnel workers suggests that better control of exposures is needed.