Ethnic inequalities in mortality among the elderly in New Zealand

Objectives: To explore the contributions of socio-economic and demographic factors to ethnic disparity among older adult (65+) all cause and cause-specific mortality differentials among Maori, Pacific, Asians and non-Maori, non-Pacific non-Asian (nMnPnA) in New Zealand. Methods: We used univariate and multivariable Poisson regression models on linked New Zealand census and mortality data for older adults (65 years and above) (2001 to 2004, 1.3 million person years) with a comprehensive set of socio-economic indicators (education, income, car access, housing tenure, neighourhood deprivation). Results: After controlling for the differences in age structure, Maori and Pacific males had a higher relative risk of dying than nMnPnA (RR=1.88 (95% Cl: 1.74, 2.04) and RR=1.75 (95% Cl: 1.54, 1.99) respectively) while Asian males had lower risk of dying (RR=0.66, 95% Cl: 0.57, 0.76). For females, the pattern was similar. The mortality gap between ethnic groups was mediated in part by socio-economic factors. The five socio-economic factors appear to account for greater than 40% of the excess mortality for Maori and Pacific men and about 34% for Maori females and 48% for Pacific females compared to nMnPnA men and nMnPnA women respectively. However, for Asian people, adjusting for socio-economic factors actually increases the relative gaps in mortality compared to nMnPnA by 18% for male and 71% for females. Conclusion: The results demonstrate that clear ethnic mortality gradients persist into old age and the mortality level of most groups was influenced by varying distribution of socio-economic factors. To reduce ethnic differences in old age mortality, inequalities as a result of socio-economic position should be reduced.