Epidemiology: Demographic Aspects

Abstract

This chapter discusses the principal epidemiological characteristics of stomach cancer as observed in a consistent manner over a period of twenty-five years. Although the numbers of cases diagnosed each year show an apparent stability with an overall small decline, further analysis demonstrates that when allowance is made for changes in the structure by age, both of the cancer cases and of the populations from which they are drawn, the rates of incidence are declining in both sexes, but more steeply in the female. A more subtle expression of the changing rates makes clear that the more recently-born groups (“cohorts”) experience, age for age, lower rates than their predecessors.