This study evaluated the prevalence of asbestos exposure-induced pleural thickening on chest radiograph in repairing shipyard workers.

A total of 2,114 incumbent and retired workers in a shipyard underwent chest radiograph, questionnaire study, interview, and physical exam from 2005 to 2007. Finally, 1,702 workers were selected and classified into two groups according to asbestos exposure: exposure and non-exposure groups. The characteristics in the exposure group were investigated.

The prevalence of pleural thickening on chest radiograph was 5.2 % and 3.1 % in the exposure and non-exposure groups, respectively (p<0.05). In those aged 50 years or above, the prevalence was 17.6 % and 8.7 % in the exposure and non-exposure groups, respectively (p<0.05). The prevalence was 16.5 % and 30.2 % and the odds ratio was 2.34 (95% CI; 1.15–4.77) and 2.95 (95%CI; 1.08–8.07) in the workers with an exposure duration of 20-29 years and more than 30 years, respectively. The prevalence was higher when considering tuberculosis history.

The prevalence was increased with increasing exposure duration was more than 20 years. The authors therefore suggest that this group should be followed up periodically by special program and that a longitudinal study with repairing shipyard workers as the cohort should be undertaken.