The course of denim sandblasting silicosis is unknown. We aimed to reevaluate former sandblasters studied in 2007 for incident silicosis, radiographic progression, pulmonary function loss, and mortality and to examine any associations between these outcomes and previously demonstrated risk factors for silicosis.
We defined silicosis on chest radiograph as category 1/0 small opacity profusion using the International Labor Organization classification. We defined radiographic progression as a profusion increase of two or more subcategories, development of a new large opacity, or an increase in large opacity category. We defined pulmonary function loss as a ≥ 12% decrease in FVC.
Among the 145 former sandblasters studied in 2007, 83 were reassessed in 2011. In the 4-year follow-up period, nine (6.2%) had died at a mean age of 24 years. Of the 74 living sandblasters available for reexamination, the prevalence of silicosis increased from 55.4% to 95.9%. Radiographic progression, observed in 82%, was associated with younger age, never smoking, foreman work, and sleeping at the workplace. Pulmonary function loss, seen in 66%, was positively associated with never smoking and higher initial FVC % predicted. Death was associated with never smoking, foreman work, number of different denim-sandblasting places of work, sleeping at the workplace, and lower pulmonary function, of which only the number of different places worked remained in multivariate analyses.
This 4-year follow-up suggests that almost all former denim sandblasters may develop silicosis, despite short exposures and latency.