Does asbestos exposure cause airway obstruction, in the absence of confirmed asbestosis?

RATIONALE: Whether occupational exposure to asbestos causes airway obstruction remains controversial.

OBJECTIVES: This study evaluated lung function in relation to cumulative exposure to asbestos in a large cohort of retired or unemployed workers exposed to asbestos.

METHODS: The study population consisted of 3,660 volunteer subjects. An individual cumulative exposure index to asbestos was calculated for each subject, and information was obtained on smoking status. Pulmonary function tests were performed in all subjects; high-resolution chest computed tomography was also performed in 3,335 subjects.

MEASUREMENTS AND MAIN RESULTS: Values of FEV(1)/FVC and FEF(25-75%) did not differ between five classes (quintiles) of cumulative exposure to asbestos, and no significant correlation was observed between cumulative exposure to asbestos and pulmonary function parameters, after adjustment for sex, tobacco consumption, emphysema, and body mass index. Furthermore, the proportion of abnormal pulmonary function tests did not differ between the five classes of cumulative exposure to asbestos.

CONCLUSIONS: The results do not support a causal relationship between asbestos exposure alone and airway obstruction. However, the study sample may not be representative of all people occupationally exposed to asbestos, because a fraction of subjects with previously diagnosed asbestosis probably did not participate in this screening program.