The impact of stomach cancer mortality on life expectancy at birth: a decomposition analysis in east Asian countries from 1990 to 2019

From 1990 to 2019, stomach cancer posed a significant health burden in East Asia. The impact of stomach cancer deaths on life expectancy at birth in East Asian countries remains underexplored. This study quantifies the impact of stomach cancer on life expectancy (LE) and decomposes the age-specific contributions of this impact from 1990 to 2019 for East Asian countries. Using Global Burden of Disease data, we utilize potential gains in life expectancy (PGLEs) at birth to assess the impact by building cause-deleted life tables. The research decomposed age-specific contributions to the impact using Arriaga's method. The findings reveal that stomach cancer deaths reduced approximately 0.35 to 1.02 years in LE at birth for males and 0.24 to 0.66 years for females in East Asian countries over the decades. The impact of stomach cancer on life expectancy in China, Japan, and South Korea converged before 2004 and then declined. A sudden drop characterized North Korea between 1995 and 2003. Notably, the patterns of age-specific contributions to the impact were heterogeneous. In China, Japan, and South Korea, the most impactful contribution in the PGLEs at birth shifted towards older age groups, while the pattern in North Korea showed limited changes. Focusing on consistent stomach cancer prevention policies could yield greater life expectancy gains, especially for older males. Despite rising life expectancy, nations with slower declines in stomach cancer mortality may face a more pronounced impact in the future.