The Influence of Age Structure on Cancer Mortality: Evidence from Italy and Europe, 2020-2022. A Methodological Note

In epidemiology, standardization is an essential tool when comparing mortality between populationswith different age structures. Using Italy, one of the oldest countries in the European Union, and theEU-27 aggregate as a case study, this methodological note demonstrates how comparisons betweencrude mortality rates can give misleading interpretations of disease burden. While crude ratessuggested a higher mortality in Italy (≈280 per 100 000) compared to the EU-27 (≈259 per 100000), standardized rates showed the reverse pattern (≈224 vs ≈239 per 100 000). A Kitagawadecomposition confirmed that the excess in crude mortality rates for Italy is almost entirelyexplained by the effect of age structure rather than true etiological factors.This methodological note illustrates the necessity of proper standardization in cancer epidemiology.All the instructions to download the official datasets and the Python scripts for the analysis areopenly available on Zenodo (doi:10.5281/zenodo.17251977), offering both an educational exampleand a methodological reference for standardization to support students, policymakers, andresearchers in applying these techniques.