Latent tuberculosis infection and risk of cancer-specific mortality: a 10-year prospective cohort study in rural China.

OBJECTIVES: We aimed to assess the association between latent tuberculosis infection (LTBI) and cancer-specific mortality in a rural Chinese population. METHODS: We analyzed data from the LATENTTB-NSTM prospective cohort, which enrolled rural residents aged ≥ 5 years from four study sites in China in 2013. LTBI status at baseline was determined using the QuantiFERON-TB Gold In-Tube assay after exclusion of active pulmonary tuberculosis. Participants were followed from enrollment until death or 31 December 2023, whichever occurred first. The primary outcome was cancer-specific mortality; secondary outcomes were all-cause and non-cancer mortality. Cox proportional hazards models were used for all-cause mortality, and Fine-Gray subdistribution hazard models accounting for competing risks were used for cancer-specific and non-cancer mortality. A 30-day landmark analysis was performed among participants with incident cancer. RESULTS: Among 21142 participants, 4428 (20.94%) had LTBI at baseline. The median age was 46 years (interquartile range: 27-59 years), and 11146 (52.72%) participants were female. During a median follow-up of 10.4 years (211498 person-years), 1798 deaths occurred, including 423 cancer-specific and 1375 non-cancer deaths. LTBI was associated with cancer-specific mortality (adjusted subdistribution hazard ratio [aSHR]=1.43, 95% CI: 1.16-1.77). No statistically significant association was observed with all-cause mortality (adjusted hazard ratio=1.08, 95% CI: 0.97-1.19) or non-cancer mortality (aSHR=1.02, 95% CI: 0.91-1.15). In the 30-day landmark analysis among participants with incident cancer, the association between LTBI and subsequent cancer-specific mortality was not statistically significant (aSHR=1.12, 95% CI: 0.89-1.41). CONCLUSIONS: In this rural Chinese cohort, LTBI was associated with cancer-specific mortality, whereas no statistically significant associations were observed with all-cause or non-cancer mortality. Further studies in other populations are needed to confirm this association and investigate the underlying mechanisms.