Persistent and widening geographic disparities in liver cancer mortality in China, 1987–2021: a 35-year analysis from a national perspective

Although liver cancer mortality in China has declined overall, long-term trends in geographic and demographic disparities remain poorly understood. This study aimed to evaluate temporal trends and evolving patterns in liver cancer mortality, focusing on subnational disparities and shifts in disease burden. Mortality data were obtained from two sources: the World Health Organization (WHO) Mortality Database (1987–2000), which provided nationally representative vital registration data stratified by urban–rural residence; and the Chinese Disease Surveillance Points (DSP) system (2004–2021), a population-based sampling network that gradually expanded to 605 surveillance sites across all 31 provinces by 2013, with continuous stratification by urban–rural and eastern–central–western regions. To assess subnational disparities, we calculated the overall and subgroup-specific temporal trends and compared regional age-standardized mortality rates (ASMRs) with the national level as reference. Age-period-cohort (APC) model was applied to decompose age, period, and birth cohort effects. Poisson models were applied to estimate the period-specific rate ratios of mortality aligning with key phases. Liver cancer mortality increased modestly until around 2004 and then declined overall through 2021 (average annual percentage change –1.09% 95% CI: –1.25%, –0.93%), with more pronounced reductions in urban and eastern areas, and slower declines in rural and western areas. Eastern and central regions contributed over 80% of the overall national decline. Males consistently had higher mortality than females, with widening sex disparities observed in rural and western areas. Younger age groups experienced greater declines, while older adults showed slower reductions or even increasing trends. APC analysis showed increased mortality risk with age, while period and cohort effects showed marked improvements, particularly among younger individuals, females, and those in eastern urban areas. In contrast, declines were limited in older age groups and western rural populations. Regional disparities in mortality widened over time, with growing rural–urban and western–eastern gaps observed in recent years. Liver cancer mortality in China remains geographically and demographically unequal, with burden shifting towards western rural regions, and persistent disparities by sex and age. These findings highlight the urgent need for region-specific and population-targeted prevention strategies, particularly for older adults and underdeveloped regions.