Association between neutrophil-lymphocyte ratio and latent tuberculosis infection in the United States: a cross-sectional study from NHANES 2011–2012

BACKGROUND: Latent tuberculosis infection (LTBI) breeds community-wide tuberculosis (TB). Early detection is the key to TB control. A novel inflammatory measure, the neutrophil-lymphocyte ratio (NLR), may be essential in this regard. However, the relationship between NLR and LTBI remains uncertain. This study aimed to investigate the association between neutrophil-lymphocyte ratio (NLR) and latent tuberculosis infection (LTBI). METHODS: This cross-sectional study utilized data from the United States National Health and Nutrition Examination Survey (NHANES) conducted in 2011-2012. Curve fitting was performed to examine the association between the NLR and LTBI. Logistic regression analysis was applied to further elucidate this relationship. In addition, stratified analyses were conducted considering various blood indicators, clinicodemographic characteristics, and other relevant variables to account for potential confounders. RESULTS: A total of 2,609 subjects were included, in which the prevalence of LTBI was 17.44% (455/2,609). Multivariate regression modeling showed that after trichotomizing for the NLR and adjusting for all covariates, the association between the NLR and LTBI in the T3 group compared with the T1 and T2 groups reached 1.79 (95% confidence interval [CI]: 1.36 to 2.37, p < 0.001) and 1.47 (95% CI: 1.11 to 1.96, p < 0.001), respectively. In subgroup analyses, the effect size of NLR in the presence of LTBI in subgroups was robust. CONCLUSION: In patients with LTBI, the NLR was negatively associated with LTBI. Assessment of NLR may be a valuable part of prevention and diagnosis in patients with LTBI.