Aims and background: Studies on migrant populations have been of great value in clarifying the role of environmental factors in cancer occurrence. Most of them consider migrants from other countries or continents. Turin, the target territory of this study, was an important area of internal migration initially from the East, and more recently from southern Italy.
Methods: The study compared incidence rates (age-standardized) of the native population, of the migrants and incidence rates of the Cancer Registries located in the four main areas of origin.
Results: Overall incidence rates in migrants from southern Italy were intermediate compared with those of the stable populations of the South and the North. The same effect was not true for people from the North-East, who migrated in earlier decades. In this population, migration towards lower-incidence areas did not reduce cancer incidence. Migrants from the South showed a significant increase in intestinal, breast, and tobacco-related tumors compared to the stable southern population. No effect of migration was found for cancer of the mouth, pharynx, esophagus, stomach or corpus uteri. Incidence of liver cancer in migrant southern males was significantly different from the stable and the native north-western population.
Conclusions: The results, based on incidence data, validated previous findings based on mortality data on the effect of Italian internal migrations and showed that migrants underwent changes in some environmental exposures. In particular, migrants from the South to the North of Italy came into contact with new risk factors, with an increase in occurrence of cancer.