Abstract
PURPOSE: This study aimed to examine secular trends, age-period-cohort effects, and geographical differences in gastric cancer (GC) mortality in Korea. MATERIALS AND METHODS: Using cause of death data from the Korean Statistical Information Service for GC from 2000 to 2020, we calculated average annual percentage changes (AAPCs) in the age-standardized mortality of GC in 17 cities and provinces through joinpoint regression. Decomposition of age, period, and cohort effects on GC mortality were elucidated by applying a log-linear model and an intrinsic estimate method. Spatial patterns and the degree of spatial clustering in 250 administrative regions were explored via Moran's I statistics. Stratification by sex was performed for all analyses. RESULTS: The age-standardized mortality of GC per 100,000 persons declined from 29.0 in 2000 to 7.9 in 2020 (AAPC, -6.28%). Age-period-cohort analyses of GC mortality showed a downward trend among five-year age groups from age 20-89 years across five-year periods from 2005-2020 and five-year birth cohorts from 1920-2000. Overall, the younger birth cohort showed lower mortality rates than the older cohort within the same period. In 2020, clusters of high GC mortality were observed in the central area for men (Chungcheongbuk, Jeollabuk, Gyeongsangbuk, and Gyeongsangnam) and in the eastern area for women (Gyeongsangbuk). CONCLUSION: This study identified a downward trend in GC mortality among men and women from 2000 to 2020 in Korea. This trend was mainly attributed to birth cohort rather than period effects. Spatial analysis showed high GC mortality in the Chungcheong and Gyeongsangbuk areas.