Risk factors for latent tuberculosis infection clustering among the elderly: a population-based cross-sectional study...

Tuberculosis (TB) remains a major global health threat. Mass screening effectively detects hidden TB cases and latent tuberculosis infections (LTBI), crucial for prevention. This study aims to use IFN-γ release assay (IGRA) screening in Deqing elderly reveals hidden TB and LTBI cases, explore the risk factors influencing the clustering of LTBI.

A cross-sectional study was conducted in 2023 among elderly residents (aged 60 years or above) in Deqing County using IGRA test (AIMTB). Participants were sampled from 13 towns or sub-districts proportional to their populations (26,234 participants, 19.01% of the elderly population aged 60 and above in Deqing). Demographic information and comorbidities were collected. Spatial autocorrelation analysis was conducted at the village level to identify LTBI clusters, and logistic regression was used to explore clustering risk factors by comparing population characteristics in hot spots versus cold spots.

Of the 26,234 participants, 25,952 with complete data and definite IGRA results were included in the analysis. 1,878 were diagnosed with LTBI, resulting in an overall prevalence of 7.34%. LTBI prevalence was higher in males (8.69% vs. 6.01%, P < 0.0001), those aged over 70 and 80 (8.80% vs. 7.24% vs. 6.66%, P < 0.001), and individuals with low or high BMI (8.06% vs. 7.91% vs. 6.75%, P < 0.0001), smokers (8.89% vs. 6.77%, P < 0.001), and alcohol consumers (8.77% vs. 6.77%, P < 0.0001). Spatial analysis revealed 18 villages as cold spots and 5 as hot spots. Multivariable logistic regression of cold and hot spots identified age (70-79) (OR = 1.550, 95% CI = 1.225-1.962, P < 0.001) and alcohol consumers (OR = 1.495, 95% CI = 1.139-1.967, P = 0.004) are clustering risk factors. BMI (< 18.5) (OR = 0.451, 95%CI = 0.319-0.637, P < 0.001), and literate are clustering protective factors (OR = 0.556, 95%CI = 0.425-0.727, P < 0.001).

This study underscores the high burden of LTBI among elderly males and individuals with certain risk factors in Deqing County. Identifying age and alcohol consumers as key factors in LTBI clustering suggests targeted interventions in high-risk villages could enhance TB prevention and control efforts.