Study On The Infection, Prevalence And Vocational Biosafety Of TB Among Employees In Henan Provincial Anti-TB Institutions

Objective To learn the infection,prevalence and vocational safety of TB among employees in Henan provincial anti-TB institutions for the reference to establish and perfect the measures,the strategies and the system of the vocational biosafety of TB.Methods Cross-sectional study and historical cohort study were adopted. In the cross-sectional study learning the prevalence of pulmonary tuberculosis(PTB),all employees in service were regarded as the surveyed subjects.X-ray and sputum smear test were used to aid the diagnosis of pulmonary tuberculosis.In the cross-sectional study learning infectious rate, the employees working in all municipal-level anti-TB institutions and the 34 county-level anti-TB institutions selected in random.The tuberculin skin test was used to test the infection.In the cross-sectional study learning the condition of vocational biosafety,all anti-tuberculosis institutions in Henan were regard as surveyed subjects.In historical cohort study,the cohort consists of all employees,healthcare workers and non-healthcare workers(i.e. administration staffs and logistic staffs)in Henan provincial anti-TB institutions from Jan 1,1995 to Dec 31,2004.The healthcare workers and non-healthcare workers were regarded as exposed group and control group respectively.Relative risk was used to measure the vocational biosafety of TB.SPSS software was use to do statistical analysis and Cox regression model was used to estimate the value of RR.Results 3748 employees in current service were accepted the test for pulmonary tuberculosis(PTB),of which male and female employees were 1808 and 1940 respectively,and health care workers and non-health care workers were 2521 and 1227 respectively.Twenty employees including 17 health care workers, three of them being smear-positive PTB(SPPTB),and 3 non-health care workers were found to suffering PTB.The prevalence rates of PTB and SPPTB among employees were 533.6/10~5 and 80.0/10~5 respectively.The prevalence rates of PTB among healthcare workers and non-health care workers were 674.3/10~5(male: 674.3/10~5;female:694.9/10~5)and 244.5/10~5(male:275.5/10~5;female:199.6/10~5) respectively.2153 employees accepted the tuberculin skin test(TST)and the positive rate and strong-reaction rate were 60.7%(health care worker:66.1%;non-health worker:48.6%)and 19.5%(healthcare worker:22.7%;non-health care worker: 12.1%)respectively,the positive rate and strong-reaction rate among the employees without BCG history were 59.8%and 18.7%respectively.There was not significant difference between BCG history and non-BCG history about positive rate and strong-reaction rate.The positive rates of TST adjusted with the weights between municipal-level and county-level among employees,health care workers,non-health care works were 57.3%,62.8%,and 45.1%,respectively.The incidence rates of TB,PTB and SPPTB among 4229 employees with retrospective survey were 449.4/10~5 person-years(PY)(health care worker: 579.1/10~5PY;non-healthcare worker:205.8/10~5PY),388.1/10~5PY(healthcare worker:490.4/10~5PY;non-healthcare worker:196.0/10~5PY)and 136.2/10~5 PY (healthcare worker:151.3/10~5PY;non-health care worker:107.8/10~5PY) respectively.The adjusted RR value of healthe care work doctor was 2.62(95%CI:1.64-4.19)with multivariate Cox regression model.The vocational safety survey about working environment was conducted in 127 anti-tuberculosis institutions.There are 13 consulting rooms,7 sputum-test labs and 21 X-ray rooms without openable windows and there are 65.4% consulting rooms,66.9%sputum-test labs and 43.3%X-ray rooms whose windows were openable andalways open for ventilation.There are 89.0%consulting rooms, 15.0%sputum-test labs and 70.1%X-ray rooms which still have the function for patient to wait to see a doctor.9.7%consulting rooms,4.7%sputum-test labs, 42.5%x-ray rooms and 12.2%wards had not ultraviolet lights for disinfection.Conclusions The TB prevalence rate,infection rate and incidence rate among employees working in the anti-TB institutions were higher than those among general population;the risk of health care workers suffering TB was higher than that of non-healthcare worker in anti-TB institutions;the condition of TB vocational biology safety in anti-TB institutions,the corresponding administration and biology safety of the health care workers were poor.