Clinical characteristics of artificial quartz stone silicosis patients / 中国职业医学

ABSTRACT

Objectives To explore and compare the clinical characteristics and risk factors for mortality between patients with artificial quartz stone silicosis and those with classic silicosis. Methods A total of 48 patients with artificial quartz stone silicosis (experiment group) and 98 patients with classic silicosis (control group) were recruited as the research subjects using the convenience sampling method. Data of clinical symptoms, laboratory tests, high-resolution computed tomography (HRCT), and pulmonary pathology of the research subjects were retrospectively analyzed. The Cox proportional hazards regression model was used to analyze the influencing factors on the survival time of silicosis patients. Results Patients in the experiment group had shorter years of dust exposure, latency period and time since last exposure than those in the control group (all P<0.01). The positive rate of anti-nuclear antibodies and the expression of neuron-specific enolase in the experiment group were higher than those in the control group (39.6% vs 10.2%, median： 28.44 vs 16.25, both P<0.01). The PaO2 levels in the experiment group were lower than those in the control group (median： 66.0 vs 89.0, P<0.01). The patients in the experiment group had lower vital capacity, inspiratory reserve volume, forced expiratory volume in the first second (FEV1), forced vital capacity (FVC), and carbon monoxide diffusion capacity compared to the control group (all P<0.05), but the maximal expiratory flow in 75% vital capacity was higher than the control group (P<0.05). Compared with the control group, patients in the experiment group had the presence of ground-glass opacity (GGO) in both lungs, aggregation and fusion of subpleural nodules, and gradual formation of progressive massive fibrosis (PMF), with higher potential of pneumothorax. Within 5 years after diagnosis, the mortality of patients in the experiment group was higher than that in the control group (27.1% vs 4.1%, P<0.01). The Cox regression model analysis results showed that patients with nodule aggregation on lung HRCT images had a higher risk of mortality than those without nodule aggregation, and lower lung function including vital capacity, FVC, FEV1 and maximum expiratory flow in 25% vital capacity had higher risk of reduced survival time (all P<0.05). Conclusion Compared with patients with classic silicosis, patients with artificial quartz stone silicosis have higher level of serum neuron-specific enolase, increasing the risk of autoimmune diseases. Pulmonary imaging features in patients with artificial quartz stone silicosis include GGO, PMF and susceptibility to pneumothorax, and rare calcification of mediastinal lymph nodes, leading to a higher mortality rate within 5 years after diagnosis.