Abstract
Abstract
Background
Enteric infections are often regarded as resolved in East Asia, yet the region spans nearly the full socio-demographic spectrum. Whether recent changes in burden reflect changes in age-specific risk or in population age structure is unknown.
Methods
Using Global Burden of Disease (GBD) 2023 estimates, we analysed age-standardised prevalence, incidence, years lived with disability, years of life lost and disability-adjusted life-years (DALYs) for diarrhoeal diseases and typhoid and paratyphoid fevers in China, Japan, the Republic of Korea, the Democratic People's Republic of Korea (DPRK), Mongolia and Taiwan from 1990 to 2023, stratified by age, sex and risk factor. Trends were summarised as estimated annual percentage change (EAPC). We decomposed the change in crude rates, using an exact log identity, into epidemiological (age-standardised rate) and demographic (population age structure) components, and characterised the age distribution of prevalent cases. Analyses were repeated with a 2022 endpoint because 2023 non-fatal estimates for China and Japan showed a discontinuity.
Results
Age-standardised prevalence of diarrhoeal diseases fell in China (EAPC − 5.16%) and Mongolia (− 4.76%) and rose in the DPRK (7.04%) and Taiwan (4.07%). Decomposition identified two mechanisms. In the DPRK the increase was almost entirely epidemiological (age-specific risk + 683.6%, ageing − 3.5%); in Taiwan risk dominated (+ 235.4%), with ageing contributing one fifth (+ 32.2%). Conversely, in the Republic of Korea a 62.0% fall in risk was offset by ageing (+ 88.8%), and in Japan crude DALY rates rose 24.0% although age-standardised rates fell 25.3%. With a 2022 endpoint, findings for the DPRK, Taiwan, the Republic of Korea and Mongolia were unchanged; in Japan the age-standardised fall narrowed to 3.6% but crude rates still rose (+ 34.6%) through ageing (+ 39.7%). The mean age of prevalent cases rose in all six settings, from 25.0 to 53.7 years in Taiwan, where the proportion aged 60 years and older rose from 20.6% to 61.2%. Typhoid and paratyphoid fevers remained rare and declined throughout.
Conclusions
Rising enteric burden in the DPRK and Taiwan reflects genuine increases in age-specific risk, whereas apparent increases in Japan are demographic. Crude and mortality-based indicators alone misread progress in rapidly ageing populations; age-standardised and crude measures should be reported together.