Vitamin D and the risk of latent tuberculosis infection: a meta-analysis

Objective: Latent tuberculosis infection (LTBI) may be a risk of developing tuberculosis (TB) and thus a health hazard. The aim of this meta-analysis is to explore the association between vitamin D and LTBI. Methods Databases including PubMed, Embase, Scopus, and ProQuest were electronically searched to identify observational or interventional studies that reported the association between vitamin D and LTBI. The retrieval time is limited from inception to September 2021. Two reviewers independently screened literature, extracted data, and assessed risk bias of included studies. Meta-analysis was performed by using STATA 12.0 software. Results A total of 5 studies involving 2 case-control studies and 3 cohort studies were included. The meta-analysis result showed that the serum level of vitamin D was associated with the risk of LTBI (OR=0.32, 95%CI: 0.12-0.85, P=0.022). The result from cohort studies suggested that relatively high vitamin D level was a protective factor for LTBI (RR=0.67, 95%CI: 0.48-0.92, P=0.015). Conclusions Our meta-analysis suggested that serum vitamin D levels were associated with LTBI, and relatively high serum vitamin D level was a protective factor for LTBI. Further RCTs are needed to verify whether vitamin D supplementation prevents LTBI.