Associations between radiographic findings and spirometry in a community exposed to Libby amphibole

• Published in: Occupational and environmental medicine (London, England) Vol. 69; no. 5; pp. 361 - 366
• Main Authors: Larson, Theodore C, Lewin, Michael, Gottschall, E Brigitte, Antao, Vinicius C, Kapil, Vikas, Rose, Cecile S
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd 01.05.2012; BMJ Publishing Group; BMJ Publishing Group LTD
• Subjects: Adolescent; Adult; Amphiboles; Asbestos; Asbestos, Amphibole - toxicity; Asbestosis - diagnostic imaging; Asbestosis - physiopathology; Biological and medical sciences; Body mass index; cancer; Chemical and industrial products toxicology. Toxic occupational diseases; Cohort Studies; Computerized axial tomography; Disease; Environment; epidemiology; Female; Fibrosis; Hazardous materials; Humans; hygiene/occupational hygiene; Inorganic dusts (pneumoconiosises) and organic dusts (byssinosis etc.); Logistic Models; Male; Medical sciences; Middle Aged; Obesity; Patients; Pleural Diseases - diagnostic imaging; Pleural Diseases - etiology; Pleural Diseases - physiopathology; pneumoconiosis; Predictive Value of Tests; public health; Radiography; respiratory; Respiratory function; Spirometry; Statistical significance; Toxicology; Vermiculite; Vital capacity; Young Adult; Montana; United States; North America; America; USA, Montana; Human; Radiography; Spirometry; Asbestos; Amphibole; Association; Cohort study; Epidemiology; Occupational medicine; Pleura; Thickening
• ISSN: 1351-0711; 1470-7926; 1470-7926
• DOI: 10.1136/oemed-2011-100316

Background Among asbestos-exposed individuals, abnormal spirometry is usually associated with parenchymal abnormalities or diffuse pleural thickening. Localised pleural thickening (LPT), the most common abnormality associated with asbestos exposure, is typically thought to be a marker of exposure with little clinical consequence. Our objective was to determine if abnormal spirometry is associated with LPT independent of other abnormalities, using data from community-based screening conducted in Libby, Montana. Methods Subjects were a subset of screening participants comprising persons with interpretable spirometry and chest radiograph results (n=6475). Chest radiographs were independently evaluated by two or three B readers, and participants were classified by mutually exclusive categories of spirometry outcome: normal, restriction, obstruction or mixed defect. Results Restrictive spirometry was strongly associated with parenchymal abnormalities (OR 2.9; 95% CI 1.4 to 6.0) and diffuse pleural thickening (OR 4.1; 95% CI 2.1 to 7.8). Controlling for the presence of these abnormalities as well as age, smoking status and other covariates, restrictive spirometry was also associated with LPT (OR 1.4; 95% CI 1.1 to 1.8). The risk of restrictive spirometric findings correlated with the severity of LPT. Conclusions In this large community-based screening cohort, restrictive spirometry is significantly associated with LPT, indicating that this abnormality may result in lung function impairment. Physicians treating patients exposed to Libby amphibole should be aware that LPT may have functional consequences.