The Prognosis Of Latent Tuberculosis Infection Among Retired Coal Workers’ Pneumoconiosis,a Follow-up Study

Pneumoconiosis is the main and most harmful occupational disease in China currently.Since 2010,the number of new reported cases of pneumoconiosis has exceeded 20,000 per year,most of them were CWP and silicosis.Meanwhile,approximately 80,000 new cases of tuberculosis are diagnosed in China every year,ranking second among Class A and B infectious diseases,and some areas has a severe epidemic situation.In 2019,there were 775,764 new cases(accounting for 8.4%of the global new cases)in China.The latest estimation shows that about a quarter of world’s population were infected with Mycobacterium tuberculosis and were in a latent infection state for a long time.If untreated,the lifetime onset risk of tuberculosis is 5%to 10%,which is even higher in immunosuppressed populations.The infection rate of latent tuberculosis in the general population is about 20%in China.Tuberculosis is one of the main complications of pneumoconiosis.Studies have also showned that patients with pneumoconiosis have a higher LTBI concurrent rate,with an infection rate of over 60%.Domestic research on the prognosis of LTBI of retired CWP patients has not been carried out yet.Based on a cross-sectional survey of LTBI patients among retired CWP in 2016,this study followed up this population,observed their LTBI prognosis,and analyzed its associated factors.We hope to provide scientific basis for exploring the law of retired CWP and formulating comprehensive prevention and control measures for this population.Objective:To study the LTBI prognosis and its influencing factors of retired CWP patients which investigated in 2016,by conducting a questionnaire survey on their working and living conditions before and after retirement.By comparing the differences,and analyzing the related factors and influencing factors of LTBI prognosis in this population,to provide scientific basis for exploring the law of retired CWP and formulating comprehensive prevention and control measures.Methods:It was carried out in two stages and lasting for 4 years(2016.10-2020.10).The first phase was a cross-sectional study to investigate the LTBI status of inpatients among retired CWP patients in a hospital from Beijing.The second phase was a follow-up study,which based on the first stage.In the follow-up study,we observed the prognosis of LTBI in this population,by collecting 3-4mL whole blood samples from the retired CWP patients for the QuantIFERON(?)TB-Gold in Tube(QFT),detecting exhaled nitric oxide,collecting influencing factors using a standardized questionnaire by face-to-face interview,and obtaining comorbidities by querying medical records.The data were entried by Epidata software and analyzed with SPSS20.0 statistical software.Results:Among the 163 retired CWP patients,the LTBI rate was 55.21%.Retired CWP patients are high-risk population for LTBI,smoking(frequent smoking[OR=8.20,95%CI:2.12～31.71],heavy smoking[OR=9.19,95%CI:2.07～40.74]),and old cerebral infarction(OR=3.06,95%CI:1.33～7.01)are the risk factors of LTBI.The follow-up study found that,the rate of LTBI in retired CWP patients changed significantly in 4 years.The overall conversion rate of LTBI was 21.38%(34/159),which the positive conversion rate was 14.0%(7/50),while the negative conversion rate was 24.11%(27/112).Compared with retired CWP patients without LTBI,those with a history of old cerebral infarction have an increased risk of persistent infection with latent tuberculosis(OR=3.08,95%CI:1.11～8.52).Conclusion:The retired CWP patient is a high-risk population of LTBI.Smoking is a risk factor for LTBI among retired CWP patients.The four-year conversion rate of LTBI for the research subjects was 21.38%(34/159),which the positive conversion rate was 14.0%(7/50),and the negative conversion rate was 24.11%(27/112).Old cerebral infarction is also a risk factor for the persistent infection of latent tuberculosis in pneumoconiosis of coal workers.Recommendations:We should continue to follow up and dynamically observe the development of LTBI.Retired CWP patients have a high comorbidity burden,but their health literacy is low.Medical workers should strength CWP patients’ health education,encourage them quit smoking,and improve their quality of life.