Are mortality differences and trends by education any better or worse in New Zealand? A comparison study with Norway, Denmark and Finland, 1980-1990s

During the 1980s and early 1990s New Zealand experienced major social and economic change, decreasing all-cause mortality rates for the majority ethnic group, and high (but falling) cardiovascular disease (CVD) mortality rates. This paper explores whether inequalities in mortality by education were greater, and increased more, in New Zealand than in Nordic countries (Denmark, Finland, Norway), and determines the contribution of CVD to these differences and trends. Methods: We used mortality rates for 30-59 year olds by education, and slope (SII) and relative (RII) indices of inequality, calculated from comparable linked census mortality data. Results: Mortality inequalities in New Zealand were at the high end of the Nordic range when standardised by age only, but were mid-range when also standardised by ethnicity. Over time, relative inequalities in all-cause mortality increased similarly in all countries. In New Zealand a large increase in inequality for cardiovascular disease (CVD) mortality was the major contributor. In contrast both CVD and other causes of death were important drivers of increasing inequalities in Nordic countries. Absolute inequalities in all-cause mortality were stable over time among males across all countries, and increased modestly among females. The contribution of CVD to absolute inequality was stable or decreasing over time in all countries. Conclusion: Overall, inequalities in mortality in New Zealand did not widen more rapidly than in northern European countries. However, rapid social and economic change may have affected trends in CVD mortality among low educated men and women, and especially the ethnic minority groups.