Age-period-cohort analysis of pulmonary tuberculosis epidemiological trends from 2005 to 2024 and forecasts for 2035 in Sichuan Province, China

Background Pulmonary tuberculosis (PTB) remains a significant public health challenge in Sichuan, China and globally. This study evaluated the effects of age, period, and cohort on PTB reported incidence in Sichuan and predicted the incidence from 2025 to 2035. The goal was to provide evidence to support the enhancement of PTB prevention and control strategies. Methods PTB case and population data of Sichuan Province from 2005 to 2024 were obtained from the China Disease Prevention and Control Information System. Trends in incidence rates were analyzed using a joinpoint regression model based on natural logarithmic transformation. An age-period-cohort (APC) model was used to analyze the effects of age, period, and cohort on PTB reported incidence. A Bayesian age-period-cohort (BAPC) model was employed to forecast PTB reported incidence over the next 11 years. Results From 2005 to 2024, a total of 1,199,575 PTB cases were reported in Sichuan Province. APC analysis revealed that the age effect peaked in the 20-24 year age group ( RR = 285.61), while period effects showed a slow decrease. The cohort effects indicated that later cohorts had progressively lower risks. Males exhibited the highest risk at ages 20-24 years, while females peaked at ages 15-19 years. The incidence trends vary in different regions. Category 1 regions (three cities) have shown an upward trend, while Category 2 regions (remaining 18 cities) are decreasing. The BAPC model predicted that the incidence for 2035 is 55.70/100,000, exceeding the 2024 rate of 53.23/100,000. Conclusions Our findings highlight significant gender and age disparities in PTB reported incidence, with males and individuals aged 15-24 years facing higher risks. Public health strategies for PTB eradication and prevention must be tailored to age and gender. PTB control in some regions presents substantial challenges and requires locally adapted strategies. Comprehensive enhancement of tuberculosis prevention and control efforts is essential to achieve the goal of ending epidemic.