Association of Beryllium Exposure and ILO Profusion Score With Decline in FVC

Introduction: Manufacturing nuclear weapons exposed workers to beryllium, asbestos, and other toxins. Beryllium causes lung fibrosis in sensitized individuals; fibrosis is evaluated by chest X-ray (CXR), which is read with the International Labor Organization's (ILO) Profusion Scale. Some question the ILO classifications' clinical relevance. Hypotheses: 1) Increasing ILO scores correlates with decreased Forced Vital Capacity (FVC), independent of age, smoking, and gender. 2) Beryllium exposure correlates with decreased FVC. Methods: The cohort of 729 beryllium-exposed former nuclear weapons workers (FWs) received CXR and spirometry. CXR's were read by three physicians blinded to each other's readings; the highest ILO rating was used. Beryllium exposure was determined by an industrial hygienist. Statistical analyses used Epi Info® and SAS 9.1v®. Results: In linear regression models controlling for age, smoking, and gender, increasing ILO scores correlated with decreasing FVC (Spearman= -0.1927; Pearson= -0.1794). In models controlling for age, gender, and smoking status, both beryllium exposure (p=0.0318) and abnormal ILO scores (p=0.0020) independently correlate with decreasing FVC. Normal ILO scores had average FVC of 88.40%, abnormal ILO scores had average FVC of 75.64%. This difference was statistically significant. ANOVA/ANCOVA analyses showed beryllium and ILO scores to both be independently associated with decline in FVC (r2=0.0543). There was no sign interaction between ILO scores and beryllium. Conclusion: Correlation of ILO scores to FVC validates use of the ILO Scale for CXR evaluation. Exposure to beryllium and other metals was associated with lower FVC. The ILO Profusion Scale is an objective method to quantify lung damage