Trends in cancer mortality rates among migrants in Australia: 1981-2007

Abstract

Background: Previous studies have shown that migrants have lower cancer mortality rates compared to the Australian-born population, particularly for colorectal and breast cancers, which are associated with an affluent lifestyle. This study seeks to update knowledge in this field by examining mortality from colorectal, stomach, lung, melanoma, breast and bladder cancers, as well as all cancers combined between 1981 and 2007.

Methods: Data were obtained from the Australian Bureau of Statistics. Average annual age and sex-standardised mortality rates were calculated for each region of birth, period of death registration and cancer site.

Results: Generally, mortality rates declined over the study period for most conditions for the majority of migrant groups. Notable exceptions included migrants from South Eastern Europe and Eastern Europe who experienced a significant increase in mortality due to all cancers combined and Australian-born individuals who recorded a significant increase in mortality due to melanoma of the skin. Migrants generally had more favourable cancer mortality outcomes, particularly for colorectal cancer and melanoma. Migrants from Southern Europe, South Eastern Europe, Chinese Asia and Southern Asia had the greatest advantage. However, migrants displayed higher rates of stomach, lung and bladder cancers than the Australian-born population.

Conclusion: The migrant advantage can in part be explained by the protective effects of diet, lifestyle and reproductive behaviours. Possible explanations for why some migrants display greater mortality from stomach and bladder cancer include the consumption of abrasive, salted and preserved foods and higher rates of smoking. Greater emphasis should be placed on targeting at-risk migrant groups through screening and education programs at migrant resource centres and community groups. The study calls for further research to explain the observed trends, which has the potential to uncover important risk and protective factors.