Latent tuberculosis infection in China, 1990-2050: GBD-informed projections for age-targeted screening.

OBJECTIVE: China bears high latent tuberculosis infection (LTBI) caseload, yet its longitudinal trends and age-specific burden remain unquantified, hindering targeted control.

METHODS: Leveraging data from the Global Burden of Disease Study 2021, we analyzed age-standardized LTBI prevalence rate (ASPR) and cases in mainland China (1990-2021). Joinpoint regression quantified temporal trends, while age-period-cohort (APC) modeling disentangled age/cohort effects. Bayesian age-period-cohort (BAPC) projected prevalence and cases to 2050.

RESULTS: From 1990 to 2021, China's LTBI cases rose by 33.28% (1990-2021) despite declining ASPR (EAPC = -0.39). This contrasts with global trends. APC analysis indicated that the risk peak was more prolonged in mainland China, spanning the age range 25-60 years, while 20-29 years age globally. Over the next three decades, China's prevalence will decline until 2036 (29,396.35/100,000), then rebound, reaching 30,184.31 by 2050. Cases peak earlier (2029: 0.42 billion) than globally (2036: 1.80 billion).

CONCLUSION: Mainland China faces a uniquely prolonged LTBI risk window and an impending burden resurgence after 2036. Prioritizing age-targeted screening for 50-69-year-olds and strengthening surveillance are critical to achieving TB elimination.