Association between low vitamin B-12 status and latent tuberculosis infection among adults.

Background and objectives: Tuberculosis (TB) remains a major public health threat worldwide, but most of the presumed infected individuals remain asymptomatic and contain Mycobacterium tuberculosis (MTB) in a latent tuberculosis infection (LTBI), and some of them will progress to active tuberculosis. Vitamin B-12 is crucial to maintain immune function, and play a role in the metabolism of MTB, while few studies investigated the impact of vitamin B-12 deficiency on tuberculosis. Therefore, we carried out the study to explore the association between vitamin B-12 deficiency and LTBI using the National Health and Nutrition Examination Surveys (NHANES).

Methods and study design: A cross-sectional study was conducted by using data from NHANES 2011-2012. Adults (aged ≥18 years) who had available data on serum Vitamin B-12, serum Methylmalonic Acid (MMA) and QuantiFERON-TB Gold In-Tube (QFT-GIT) results were included in the analysis. Multivariable logistic regression was used to assess the association between Vitamin B-12 deficiency and LTBI.

Results: A total of 4773 subjects were included in the present study, of whom 479 were screened as LTBI. The LTBI group had a higher proportion of participants with low Vitamin B-12 status. After adjusting for the possible confounders, Vitamin B-12 deficiency was independently associated with a 37% increased odds ratio of LTBI in the participants (OR: 1.37; 95% CI: 1.01-1.85). Similar correlations remained in subjects aged ≥35 years and female subjects by further stratified analysis.

Conclusions: Vitamin B-12 deficiency was significantly associated with higher prevalence of LTBI in US adults. Maintenance of optimal Vitamin B-12 status has potential benefits for LTBI prevention. Future studies are needed to assess the roles and clinical implications of Vitamin B-12 in MTB infection.