Cancer mortality in migrant populations within Italy.
Italian death certification rates from all causes of death, all diseases of the circulatory system, all neoplasms, and cancers of the upper digestive and respiratory tract, stomach, intestines, lung and breast in middle age (45-64 years) were analyzed according to selected geographic areas of birth and residence at death. For total cancer mortality and most neoplasms considered, the rates in middle age were closer to those of place of birth than to those of area of residence, although this pattern was more evident for some sites (e.g., mouth or pharynx, esophagus, larynx, stomach or bladder) than for others (e.g., intestines or breast). In most cases, migration had an adverse effect on cancer rates, and the lowest mortality was reported among stable populations (i.e., those with the same area of birth and death). These findings are discussed in relation to the major migration fluxes within Italy during the current century. Moreover, these analyses give information on the quality of Italian cancer death certification, since the observation that area of birth is often a more important determinant of cancer rates than area of residence provides indirect evidence that cancer death certification in various Italian geographic areas is satisfactorily reliable and consistent.