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

## TL;DR

This study projects the future of latent tuberculosis infection in China, showing a prolonged risk period and a predicted resurgence after 2036.

## Contribution

The study provides novel age-targeted projections of latent tuberculosis infection in China using GBD data and Bayesian modeling.

## Key findings

- China's LTBI cases increased by 33.28% from 1990 to 2021 despite a declining ASPR.
- The risk peak for LTBI in China spans ages 25–60, longer than the global 20–29 range.
- LTBI prevalence in China is projected to rebound after 2036, reaching 30,184.31 per 100,000 by 2050.

## Abstract

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

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.

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).

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.