Cancer risk related to uncommon migration within Italy

Given the industrialization in Italy over this past century much migration has occurred within the country especially from southern to northern regions. Following repeated drainings of the pre-existing marsh area (Pontina plain) during the 1930s the Latina province received an unusual north-south immigration from the regions of Veneto, Friuli and Emilia Romagna. This consisted principally of manual workers, farmers and their families. Four new towns developed after a few years (Littoria, later renamed Latina, Sabaudia, Pontinia and Aprilia), and the whole province quickly reached a population of 60,000. The availability of a population-based Cancer Registry in the Latina province allowed us to assess the cancer risk in this migrant population.

Standardized Incidence ratios (SIRs) according to cancer site and sex were computed for residents over the age of 55 years, born in northern Italy. Population data, by sex, age and region of birth were based on the 1981 census. The age-sex-site specific incidence rates for the 1983-1987 period for the entire population of the Latina province over 55 years of age were used as standard.

A significant excess of cancer risk for subjects of both sexes born in northern Italy was found. In addition, a statistically significant higher risk was observed for the cancers of the lung, skin (non-melanomas) and prostate in males, and of the mouthpharynx, lung and skin (non-melanomas) in females.

SIRs for all sites confirm the findings from other studies on migrants in Italy and strongly support the hypothesis that the place of birth has an important influence on the frequency of cancer. Some possible etiological factors are suggested for cancer sites with higher frequencies in northern-born subjects.