OVARIAN-CANCER MORTALITY AMONG IMMIGRANTS IN AUSTRALIA AND CANADA

This study examined the impact of changing environments on ovarian can cer by comparing age-standardized mortality rates of numerous immigran t groups in Australia and Canada to those in the origin countries for the period 1984-1988. Mortality rates by length of residence in Austra lia (0-29 and 30+ years) were also calculated. In Australia, the morta lity rates for all four immigrant groups from low-risk countries and 5 3.8% from high-risk countries (n = 13) shifted toward the rate of the native-born Australians. In Canada, rates for 88.9% of immigrant group s from low-risk countries (n = 9) and 30.0% from high-risk countries ( n = 10) converged to the rate of native-born Canadians. Among individu al immigrant groups there was not a consistent pattern of convergence with length of residence in Australia. There was evidence of convergen ce among the long-term residents of some of the groups and in the aggr egate analysis. The increased mortality among the majority of immigran t 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 analyses suggests that long-term environmental and lifestyle factors in the new place of residence may also influence ovarian cancer mortal ity.