Decades of disparity: widening ethnic mortality gaps from 1980 to 1999

N Z Med J. 2004 Aug 6;117(1199):U995.


Background: Maori and Pacific deaths were severely undercounted in the mid-1980s and first half of 1990s, resulting in numerator-denominator bias when calculating mortality rates by ethnicity. We used the New Zealand Census-Mortality Study to adjust for this bias and calculate corrected ethnic-specific mortality rates from 1980 to 1999.

Methods: Age-specific adjusters were calculated for the period 1980-99. They were applied to mortality data to obtain a corrected number of deaths. Mortality rates (by age and gender) were calculated by dividing the total number of adjusted deaths by the respective census counts.

Results: Contrary to unadjusted rates, corrected Maori and Pacific mortality rates were clearly higher than non- Maori non-Pacific rates during the 1980s and early 1990s. From 1980-84 (1361 per 100,000 for males and 965 per 100,000 for females) to 1996-99 (1258 and 894), there was only a modest decrease in Maori 1 to 74 year old mortality rates. Pacific mortality rates changed little from 1980-84 (1264 and 672) to 1996-99 (1144 and 696 per 100,000 for males and females respectively). Non-Maori non-Pacific mortality rates, however, decreased by about 30% from 1980-84 (919 and 553) to 1996-99 (641 and 407 per 100,000 for males and females, respectively). Cancer (lung, prostate, breast, colorectal) mortality rates tended to increase over time among Maori compared to steadily decreasing among non-Maori non-Pacific. Of note, Pacific colorectal cancer mortality rates have increased by about ten-fold during the 1980s and 1990s. All ethnic groups experienced falls in cardiovascular disease mortality rates, but the decreases were much greater among non-Maori non-Pacific.

Conclusion: The gaps between Maori and non-Maori non-Pacific mortality widened over the 1980s and 1990s mainly due to steadily declining non-Maori non-Pacific mortality rates and stagnant Maori mortality rates. Likewise, the gaps between Pacific and non-Maori non-Pacific mortality also widened during that period.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Cardiovascular Diseases / ethnology
  • Cardiovascular Diseases / mortality
  • Child
  • Child, Preschool
  • Female
  • Humans
  • Infant
  • Male
  • Middle Aged
  • Mortality / trends*
  • Native Hawaiian or Other Pacific Islander / statistics & numerical data*
  • Neoplasms / ethnology
  • Neoplasms / mortality
  • New Zealand / epidemiology
  • Suicide / ethnology
  • Suicide / trends
  • Whites / statistics & numerical data*
  • Wounds and Injuries / ethnology
  • Wounds and Injuries / mortality