Age, period and cohort effects on gastric cancer mortality in Spain, 1980-2021

This study aimed to evaluate the effects of age, period and cohort (A-P-C) on gastric cancer (GC) mortality in Spain from 1980-2021.We conducted an ecological trend study (with aggregated data obtained from the National Institute of Statistics). Joinpoint regression software was used to estimate rates by sex and age group (<35, 35-64, >64 years) and mortality trends. National Cancer Institute A-P-C tools were used to assess the effects of age, time of death, and birth cohort.GC mortality rates in Spain decreased significantly for both sexes in Spain. In the under-35 age group, rates were stable after an initial significant decline. In the 35-64 age group, the decline was more pronounced in men than in women. In the 65+ age group, rates fell significantly for both sexes, but more so for women than for men. The net drift and local drift also showed significant decreases for all age groups from 24 years onwards. GC mortality rates increased with age and decreased with calendar time and successive birth cohorts, regardless of sex. The ratio of age-specific rates between men and women increased with age, and birth cohort relative risk estimates followed a steady downward trend until the mid-1970s, after which the decline stabilized. The relative risk decreased for both sexes, with a more pronounced decrease in men.GC mortality rates in Spain have been decreasing over time and across successive birth cohorts, with a stabilising trend observed for those under 35 years of age.