Prevalence of latent tuberculosis infection in older adults: a systematic review and meta-analysis.

Background: The burden of tuberculosis (TB) is increasingly borne by older adults. Several studies have investigated the prevalence of latent tuberculosis infection (LTBI) in special populations. However, the global estimates of the prevalence of LTBI in older adults are unclear. This study aimed to assess the prevalence of LTBI amongst older adults.

Methods: We conducted a systematic search of PubMed, Web of Science, Scopus and Embase databases. A systematic review and meta-analysis of relevant research articles published between 1 January 2000 and 28 February 2025 was performed. The I2 and Cochran's Q statistical tests were used to assess heterogeneity. Funnel plots and Egger's test were used to examine publication bias. Meta-regression and subgroup analyses were performed to assess the sources of heterogeneity.

Results: A total of 20 studies were finally included in this study after screening the articles. The overall pooled prevalence of LTBI in older adults was 31.1% [95% confidence intervals (CIs): 22.8%-39.3%]. Subgroup meta-analyses revealed significant differences in the prevalence of LTBI between countries when categorised by WHO regions and WHO TB incidence intervals. Besides, the prevalence of LTBI was 30.9% (95% CI: 23.9%-37.9%) and 33.4% (95% CI: 25.9%-40.8%) based on studies that utilized interferon-gamma release assay and tuberculin skin test, respectively.

Conclusions: The prevalence of LTBI is relatively high amongst older adults, emphasising the high burden of undetected infection in this population. Future research integrating cost-effectiveness analyses and intervention studies is needed to further explore the feasibility of population-based screening and prevention strategies to promote TB prevention and control.