Ovarian cancer mortality among immigrants in Australia and Canada.

This study examined the impact of changing environments on ovarian cancer by comparing age-standardized mortality rates of numerous immigrants groups in Australia and Canada to those in the origin countries for the period 1984-1988. Mortality rates by length of residence in Australia (0-29 and 30+ years) were also calculated. In Australia, the mortality rates for all four immigrant groups from low-risk countries and 53.8% from high-risk countries (n = 13) shifted toward the rate of the native-born Australians. In Canada, rates for 88.9% of immigrant groups from low-risk countries (n = 9) and 30.0% from high-risk countries (n = 10) converged to the rate of native-born Canadians. Among individual immigrant groups there was not a consistent pattern of convergence with length of residence in Australia. There was evidence of convergence among the long-term residents of some of the groups and in the aggregate analysis. The increased mortality among the majority of immigrant groups is consistent with the reported inverse relationship between parity and ovarian cancer and the generally lower parity of immigrant women compared to those in their home country. The period of residence and analyses suggests that long-term environmental and lifestyle factors in the new place of residence may also influence ovarian cancer mortality.