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The tables in this statistical annex present information on population health in WHO Member States and regions for the year 2003 (Annex Tables 1, 2a and 2b), under-five and neonatal causes of deaths for 2000-2003 (Annex Tables 3 and 4), selected national health accounts aggregates for 1998-2002 (Annex Tables 5 and 6), and selected indicators related to reproductive, maternal and newborn health (Annex Tables 7 and 8). These notes provide an overview of concepts, methods and data sources, together with references to more detailed documentation. It is hoped that careful scrutiny and use of the results will lead to progressively better measurement of core indicators of population health and health system financing.
The theme of The World Health Report 2005 is maternal and child health. The latest estimates of under-five mortality and causes of death are now available, so special consideration is given both to estimates and to the empirical basis of under-five mortality and causes of death. Annex Table 3 on the estimated number and distribution of deaths by cause focuses on the deaths of children under the age of five years. For the first time, the estimated numbers of deaths for neonates by cause are being published (as Annex Table 4). Consequently, the table on estimated deaths by cause, sex and mortality stratum that appeared in earlier World Health Reports is not being published here.
Of the eight major goals set at the United Nations Millennium Summit in 2000, six relate directly to the health and well-being of women and children. These Millennium Development Goals (MDGs) reflect a thorough recognition by governments that improving the well-being of individuals is a prerequisite to economic development. In order to monitor progress in achieving the MDGs as well as major childhood health initiatives, a reliable information base is critical.
It is essential for the United Nations to disseminate identical estimates on the MDGs, including under-five mortality, in order to enhance proper use of these figures in policy planning or in programme monitoring and evaluation. There is thus an urgent need to develop a system through which the United Nations speaks with a single voice and produces estimates that agree. Four specialized agencies--WHO, the United Nations Children's Fund (UNICEF), the United Nations Population Division, and the World Bank--organized a meeting on child mortality (infant and under-five mortality rates) in May 2004. Meeting participants agreed on the following actions to further explore their joint activities to improve the estimation process on a regular basis: creation of a common database; discussion on the issues of the currently used methods and ways for improvement; and more focus on country capacity building and training to improve data availability and quality.
Accordingly, WHO and UNICEF produced a consistent set of under-five mortality rates by country for the period 1990-2003, which was used as the basis for estimation shown in Annex Tables 1 and 2a. It should be emphasized that such estimates may not be directly derived from reported data. Annex Table 2b summarizes the empirical basis for the estimation of under-five mortality by age group.
WHO is the primary organization to provide estimates on cause-specific mortality. A major problem has been the lack of accurate cause-specific mortality data from developing countries, especially those with higher levels of mortality. In collaboration with its regional offices, WHO headquarters collects cause-of-death data from its 192 Member States. An established agreement between headquarters and the regional offices ensures that there is no duplication of work at the country level to report data to WHO. The WHO Regional Offices for the Americas, Europe and the Eastern Mediterranean deploy simultaneous efforts to ensure that data are received in a regular and timely manner. Data from the African Region are virtually non-existent and account for the major difficulties in assessing the level of cause-specific mortality in that area.
The data submitted by Member States then become part of WHO's unique historical database on causes of death (WHO Mortality Database) which contains data as far back as 1950 (1). During 2000-2003 some 100 Member States provided vital registration data to WHO and captured approximately 18 million deaths. It should be noted, however, that more than two thirds of deaths in the world are not being reported.
These data gaps need to be .filled both by stepping up efforts to work with countries and initiatives to obtain more recent mortality data and by collaborating with partners to promote better tools and investment in data collection and analysis. There is also a need for better harmonization of cause-specific mortality estimates within WHO, with other organizations in the United Nations system and with academic institutions.
In 2001, WHO established the Child Health Epidemiology Reference Group (CHERG) to help improve estimates of cause-specific mortality in childhood. This group of independent technical experts has developed and applied rigorous standards for the development of estimates related to the major causes of childhood deaths, and worked closely with WHO and UNICEF to incorporate their results into broader WHO child health estimates at global, regional and when possible country level. Further detail on CHERG methods and products is available elsewhere (2). The results of WHO collaboration with the CHERG and UNICEF are presented in Annex Tables 3 and 4.
These estimates have been reviewed, agreed upon and supported by the WHO Departments of Child and Adolescent Health and Development (CAH) and Measurement and Health Information Systems (MHI), the UNICEF Division of Policy and Planning (DPP) and an independent group of external experts. Initial WHO estimates and technical explanations were sent to Member States for comment. Comments or data provided in response were discussed with them and incorporated where possible. The estimates published here should, however, still be interpreted as the best estimates of WHO rather than the official viewpoint of Member States.
ANNEX TABLE 1
All estimates of population size and structure for 2003 are based on the demographic assessments prepared by the United Nations Population Division (3). These estimates refer to the de facto population, and not the de jure population in each Member State. The annual growth rate, the dependency ratio, the percentage of population aged 60 years and more, and the total fertility rate are obtained from the same United Nations Population Division database.
To assess overall levels of health achievement, it is crucial to develop the best possible assessment of the life table for each country. Life tables have been developed for all 192 Member States for 2003 starting with a systematic review of all available evidence from surveys, censuses, sample registration systems, population laboratories and vital registration on levels and trends in under-five and adult mortality rates. This review benefited greatly from a collaborative assessment of under-five mortality levels for 2003 by WHO and UNICEF. WHO uses a standard method to estimate and project life tables for all Member States using comparable data. This may lead to minor differences compared with official life tables prepared by Member States.
Life expectancy at birth, the probability of dying before five years of age (under-five mortality rate) and the probability of dying between 15 and 60 years of age (adult mortality rate) derive from life tables that WHO has estimated for each Member State. Procedures used to estimate the 2003 life table differed for Member States depending on the data availability to assess child and adult mortality. Because of increasing heterogeneity of patterns of adult and child mortality, WHO has developed a model life table system of two-parameter logit life tables, and with additional age-specific parameters to correct for systematic biases in the application of a two-parameter system, based on about 1800 life tables from vital registration judged to be of good quality (4). This system of model life tables has been used extensively in the development of life tables for those Member States without adequate vital registration and in projecting life tables to 2003 when the most recent data available are from earlier years. Estimates for 2003 have been revised to take into account new data received since publication of The World Health Report 2004 for many Member States and may not be entirely comparable with those published in the previous reports. The methods used to construct life tables are summarized below and a full detailed overview has been published (4, 5).
For Member States with vital registration and sample vital registration systems, demographic techniques (Preston-Coale method, Brass Growth-Balance method, Generalized Growth-Balance method and Bennett-Horiuchi method) were first applied to assess the level of completeness of recorded mortality data in the population above five years of age and then those mortality rates were adjusted accordingly (6). Where vital registration data for 2003 were available, these were used directly to construct the life table. For other countries where the system provided a time series of annual life tables, the parameters ([I.sub.5], [I.sub.60]) were projected using a weighted regression model giving more weight to recent years (using an exponential weighting scheme such that the weight for each year t was 25% less than that for year t+1). For countries with a total population of less than 750 000 or where the root mean square error from the regression was greater than or equal to 0.011, a shorter-term trend was estimated by applying a weighting factor with 50% annual exponential decay. Projected values of the two life table parameters were then applied to a modified logit life table model, using the most recent national data as the standard, which allows the capture of the most recent age pattern, to predict the full life table for 2003.
For all Member States, other data available for child mortality, such as surveys and censuses, were assessed and adjusted to estimate the probable trend over the past few decades in order to predict the child mortality in 2003. A standard approach to predicting child mortality was employed to obtain the estimates for 2003 (see Annex Table 2a for more details) (7). Those estimates are, on the one hand, used to replace the under-five mortality rate in life tables of the countries that have a vital registration or sample vital registration system, but with incomplete registration of numbers of deaths under the age of five years. On the other hand, for countries without exploitable vital registration systems, which are mainly those with high mortality, the predicted under-five mortality rates are used as one of the inputs to the modified logit system. Adult mortality rates were derived from either surveys or censuses where available; otherwise the most likely corresponding level of adult mortality was estimated based on regression models of child versus adult mortality as observed in the set of approximately 1800 life tables. These estimated child and adult mortality rates were then applied to a global standard, defined as the average of all the life tables, using the modified logit model to derive the estimates for 2003.
It should be noted that the logit model life table system using the global standard does not capture high HIV/AIDS epidemic patterns, because the observed underlying life tables do not come from countries with the epidemic. Similarly, war deaths are not captured because vital registration systems often break down in periods of war (8). For these reasons, for affected countries, mortality without deaths attributable to HIV/AIDS and war was estimated and separate estimates of deaths caused by HIV/AIDS and war in 2003 were added.
The main results in Annex Table 1 are reported with uncertainty intervals in order to communicate to the user the plausible range of estimates for each country on each measure. For the countries with vital registration data projected using time series regression models on the parameters of the logit life table system, uncertainty around the regression coefficients has been accounted for by taking 1000 draws of the parameters using the regression estimates and variance covariance matrix of the estimators. For each of the draws, a new life table was calculated. In cases where additional sources of information provided plausible ranges around under-five and adult mortality rates the 1000 draws were constrained such that each life table produced estimates within these specified ranges. …