Prevalence of latent tuberculosis infections among residents in Nanchuan District / 预防医学

ABSTRACT

Objective@#To investigate the current prevalence of latent tuberculosis infection (LTBI) among residents living in Nanchuan District, Chongqing Municipality, so as to provide the evidence for formulating LTBI control measures.@*Methods@#The residents living in one street and one township from Nanchuan District were randomly selected using the multistage cluster sampling method during the period between January and April, 2020, and their demographic information, smoking history, history of alcohol consumption, history of contacts with tuberculosis patients and Bacillus Calmette-Guérin ( BCG ) vaccination scars were collected. The infection of Mycobacterium tuberculosis was detected using interferon gamma release assay ( IGRA ), and a positive IGRA test and exclusion of active tuberculosis was defined as LTBI. The prevalence of LTBI was descriptively analyzed among the study subjects.@*Results@#Totally 1 000 residents were recruited, including 381 males and 619 females, with a male to female ratio of 0.62∶1. The mean age was ( 45.87±18.40 ) years. Among all participants, there were 222 smokers ( 22.20% ), 247 subjects consuming alcohol (24.70%), 62 subjects with a history of contacts with tuberculosis patients ( 6.20% ) and 904 subjects with BCG scars ( 90.40% ). A total of 198 residents were diagnosed with LTBI (19.80% prevalence), and a higher prevalence rate of LTBI was seen in men than in women ( 23.36% vs. 17.61%; χ2=4.911, P=0.027 ). The prevalence of LTBI was significantly higher in married/divorced/widowed residents than in unmarried residents ( 24.22% vs. 2.01%; χ2=49.514, P<0.001 ), and significantly greater prevalence was found in smokers than in non-smokers ( 27.93% vs. 17.48%; χ2=11.871, P=0.001 ). The prevalence of LTBI appeared a tendency towards a rise with age ( χ2trend=59.100, P<0.001 ) and body mass index ( χ2trend=9.479, P=0.002 ).@*Conclusions@#The prevalence of LTBI is high among residents living in Nanchuan District, notably among elder, male smokers with high body mass index. Risk monitoring and timely interventions are required.