Serum Heme Oxygenase-1 as a Marker of Lung Function Decline in Patients With Chronic Silicosis

Objective: To identify predictive factors of excess decline in forced expiratory volume in one second (FEV1) in patients with chronic silicosis. Methods: Forty-six male patients enrolled in 2004 were screened and received pulmonary function tests. Results: Among the 33 included patients, 12 were categorized as rapid decliners (reduction in FEV1 > 60 mL/yr). The mean level of serum heme oxygenase-1 (HO-1), a marker of oxidative stress, was significantly lower in rapid decliners than in normal decliners (P = 0.002). Logistic regression analysis revealed that serum HO-1 was a factor affecting clinically important decline in FEV1 (odds ratio = 0.52; 95% confidence interval, 0.31 to 0.88) independent of the effects of age, height, weight, smoking, exposure status, and C-reactive protein. Conclusions: Serum HO-1 may be a predictor of lung function decline in silicosis patients.