The tuberculosis prevalence and risk factors among silicotic patients

Abstract

Objective To investigate the prevalence of tuberculosis among silicosis patients and silica exposure patients, and to analysis the risk factors of tuberculosis among these population. Methods A total of 1 227 silica exposure patients from Wenling, Zhejiang were enrolled in this field study. Basic demographic information was collected and chest X-ray was taken for each patient. Sputum was collected for Mycobacterium tuberculosis culture and strain identification. In univariate analysis, t test was performed for continuous variables and χ2 test for categorical variables. In multivariate analysis, the odds ratio (OR) was calculated along with a 95% confidence interval (CI) by binary Logistic regression. Results A total of 1 204 silica exposure patients had full basic information and 99.8% were male patients with mean age of (59.4±6.8) years. The patients in phase 0+ to phase Ⅲ were 172(14.3%), 255(21.2%), 160(13.3%) and 617(51.2%), respectively. The tuberculosis prevalence rate was about 7.3% among these population. The risk factors for tuberculosis including phase Ⅱ silicosis (OR=2.96, 95%CI: 1.05–8.32, P=0.04) and phase Ⅲ silicosis (OR=3.88, 95%CI: 1. 58–9.56, P<0.01), and contacting with tuberculosis patients (OR=4.14, 95%CI: 1.91–8.98, P<0.01). Patients complicated with tuberculosis lacked specific symptoms, but fever and weight loss were more frequent. Conclusion Tuberculosis is highly prevalent in silicotic patients, especially in patients with phase Ⅱ/Ⅲ silicosis and in patients with tuberculosis contact history. Key words: Tuberculosis; Silicosis; Silica dust; Risk factors