Contemporary patterns of Pacific Island mortality

The Pacific Island countries are at different stages of the demographic and epidemiological transitions. The availability of accurate and current mortality data is of vital importance for priority setting in health. Available mortality data generally underestimate death rates among both children and adults. In many Pacific Island populations, little is reliably known about levels and causes of death, particularly among adults.

The results of two comprehensive approaches to obtaining mortality estimates are reported. First, a systematic review of available life expectancy and infant mortality information reported by countries from 1990 onwards was undertaken and evaluated with respect to quality, and a final "best estimate" was established. Methods were based on registered deaths and indirect demographic methods. The second approach consisted of a demographic evaluation of vital registration data for completeness, with death rates adjusted accordingly, or where vital registration was not available, the application of new model life table methods to generate life tables from estimates of child mortality, as used by the World Health Organisation (WHO).

This analysis reveals substantial uncertainty about mortality conditions in Pacific Island populations. In some countries, life expectancy variations of 10 years or more were recorded in the 1990s, depending on the source. Best approaches suggest that life expectancy (at birth) varied considerably, from levels of around 55-60 years in some Melanesian and Micronesian states to levels above 70 years in low-mortality countries. The principal issues with regard to uncertainty around mortality levels include underenumerated vital registration data; annual stochastic fluctuations in mortality in small populations; errors in the imputation of adult mortality from infant and childhood rates; implausible results from indirect demographic methods; use of possibly inappropriate model life tables to adjust death data or for indirect methods; and inadequately described and implausible projections. The WHO model life table method based on adjusted vital registration generally yielded results similar to those suggested by an evaluation of published data, with some exceptions, which are further discussed.

This study indicates the urgent need to improve infrastructure, training, and resources for routine mortality estimation in many Pacific Island countries in order to better inform and evaluate health and public policy.