Cancer mortality in migrants from the British Isles and continental Europe to New South Wales, Australia, 1975-1995.

Routinely collected data for New South Wales were used to analyse cancer mortality in migrants from the British Isles, southern Europe and eastern Europe according to duration of residence in Australia. A case-control approach compared deaths from cancer at one site with deaths from all other cancers, adjusting for age, sex and calendar period. Compared with the Australia-born, migrants had a significantly lower risk of dying from cancers of the mouth/pharynx and prostate (migrants from each region), colon/rectum (from the British Isles and southern Europe) and lung (female southern European migrants), evident from the time of migration and maintained for 30 years after migration. Whereas a deficit of deaths from colorectal cancer remained in migrants from southern Europe, a clear gradient of increasing risk with duration of stay in Australia was apparent. A similar trend was seen with respect to kidney cancer in southern European migrants. Persistent excess risks of death from stomach cancer were seen in all migrant groups, from lung cancer in British migrants and from liver cancer in southern and eastern European migrants. Although the risk of death from breast cancer increased significantly with duration in Australia in southern European migrants, the increase was not monotonic, as the relative risk in the first 10 years after migration was almost the same as that after more than 30 years. The pattern of risk for cancers of the prostate and mouth/pharynx suggests some protective role for inheritance or maintained cultural factors.