Occupations associated with bullae on chest radiographs in Japanese middle-aged men

Objectives: To examine an association between occupation and bullae seen on chest radiographs. Methods: We performed a cross-sectional study of 27,361 men in their 50s who consulted our institute for health screening. Logistic models that independently incorporated occupation, age and smoking as variables in a stepwise fashion were selected. Results: Age and smoking significantly increased the odds ratio of the risk for developing bullae. For 19 occupations, the transport and the wholesale and retail trade industries were associated with significantly increased risk (odds ratios 1.6 and 1.5, respectively). In the transport industry, warehousing in particular showed increased risk by approximately 2.7-fold (95% CI 1.5–4.9). Road passenger transport, road freight transport, and retail were also associated with increased risk [odds ratios (5% CI) 1.3 (1.2–1.6), 1.4 (1.2–1.6) and 1.3 (1.04–1.5), respectively]. Conclusions:: The finding of the present study suggests that independently of age or smoking, the prevalence of a bulla is associated with the warehouse, road transport, and retail industries in which workers may be remarkably exposed to exhaust gas.