Results of spirometry among individuals in a silicosis registry

To determine whether individuals with simple silicosis have obstructive and restrictive decrements.

The prevalence of spirometric abnormalities by radiograph profusion, smoking, duration, and latency from first silica exposure was evaluated among confirmed silicotics.

Among 526 silicotics, 17.3% who had never smoked and 26.5% of smokers had obstruction, 30.1% and 28.1% had restriction, and 22.4% and 25.7% had a mixed obstructive and restrictive pattern. Individuals with category 3 profusion or progressive massive fibrosis were more likely to have abnormalities.

Both obstructive and restrictive patterns were observed regardless of smoking status with a low profusion category of simple silicosis. There was an increased prevalence of restrictive changes with increased profusion. After controlling for age, smoking, and duration of exposure to silica, there was a statistically significant increased risk of obstructive and mixed changes with progressive massive fibrosis.