Chapter 1: Global Health: today's challenges
Surviving the first five years of life
Although approximately 10.5 million children under 5 years of age still die every year in the world, progress has been made since 1970, when the figure was more than 17 million. These reductions did not take place uniformly across time and regions, but the success stories in developing countries demonstrate clearly that low mortality levels are attainable in those settings. The effects of such achievements are not to be underestimated. If the whole world were able to share the current child mortality experience of Iceland (the lowest in the world in 2002), over 10 million child deaths could be prevented each year.
Today nearly all child deaths occur in developing countries, almost half of them in Africa. While some African countries have made considerable strides in reducing child mortality, the majority of African children live in countries where the survival gains of the past have been wiped out, largely as a result of the HIV/AIDS epidemic.
Across the world, children are at higher risk of dying if they are poor. The most impressive declines in child mortality have occurred in developed countries, and in low-mortality developing countries whose economic situation has improved. In contrast, the declines observed in countries with higher mortality have occurred at a slower rate, stagnated or even reversed. Owing to the overall gains in developing regions, the mortality gap between the developing and developed world has narrowed since 1970. However, because the better-off countries in developing regions are improving at a fast rate, and many of the poorer populations are losing ground, the disparity between the different developing regions is widening.
Child mortality: global contrasts
Regional child mortality levels are indicated in Figure 1.4. Of the 20 countries in the world with the highest child mortality (probability of death under 5 years of age), 19 are in Africa, the exception being Afghanistan.
A baby born in Sierra Leone is three and a half times more likely to die before its fifth birthday than a child born in India, and more than a hundred times more likely to die than a child born in Iceland or Singapore. Fifteen countries, mainly European but including Japan and Singapore, had child mortality rates in 2002 of less than 5 per 1000 live births. Estimated child mortality rates for 2002 are given for all WHO Member States in Annex Table 1.
Child mortality: gender and socioeconomic differences
Throughout the world, child mortality is higher in males than in females, with only a few exceptions. In China, India, Nepal and Pakistan, mortality in girls exceeds that of boys. This disparity is particularly noticeable in China, where girls have a 33% higher risk of dying than their male counterparts. These inequities are thought to arise from the preferential treatment of boys in family health care-seeking behaviour and in nutrition.
There is considerable variability in child mortality across different income groups within countries. Data collected by 106 demographic and health surveys in more than 60 countries show that children from poor households have a significantly higher risk of dying before the age of 5 years than the children of richer households. This is illustrated in Figure 1.5, using the results for three countries from different regions. The vertical axis represents the probability of dying in childhood (on a zero to one scale). The horizontal axis shows the information by "poor" and "non-poor".1 The identification of poor and non-poor populations uses a global scale based on an estimate of permanent income constructed from information on ownership of assets, availability of services and household characteristics. This approach has the advantage of allowing comparison of socioeconomic levels across countries. It implies that the individuals defined as poor in Bangladesh have the same economic status as the population defined as poor in Bolivia or Niger.
There are significant differences in child mortality risks by poverty status in all countries, although the size of the gap varies; the risk of dying in childhood is approximately 13 percentage points higher for the poor than for the non-poor in Niger but less than 3 percentage points higher in Bangladesh.
Child mortality rates among the poor are much higher in Africa than in any other region despite the same level of income used to define poverty. The probability of poor children in Africa dying is almost twice that of poor children in the Americas. Likewise, better-off children in Africa have double the probability of dying than their counterparts in the Americas. Moreover, better-off children in Africa have a higher mortality risk (16%) than poor children in the Americas, whose risk of death is 14%.
Child survival: improvements for some
The last three decades have witnessed considerable gains in child survival worldwide (shown by WHO region in Figure 1.6). Global child mortality decreased from 147 per 1000 live births in 1970 to about 80 per 1000 live births in 2002. The reduction in child mortality has been particularly compelling in certain countries of the Eastern Mediterranean and South-East Asia Regions and Latin America, while that of African countries was more modest. Gains in child survival have also occurred in rich industrialized nations, where levels of mortality were already low.
Although child mortality has fallen in most regions of the world, the gains were not consistent across time and regions. The greatest reductions in child mortality across the world occurred 20--30 years ago, though not in the African or the Western Pacific Regions, where the decline slowed down during the 1980s, nor in some eastern European countries, where mortality actually increased in the 1970s. Over the past decade, only countries of the South-East Asia Region and the higher mortality countries in Latin America have further accelerated their reduction in child mortality.
The most impressive gains in child survival over the past 30 years occurred in developing countries where child mortality was already relatively low, whereas countries with the highest rates had a less pronounced decline. Despite an overall decline in global child mortality over the past three decades, the gap between and within developing regions has widened.
Although the chances of child survival among less developed regions of the world are becoming increasingly disparate, the gaps in child mortality among affluent nations have been closing over the past 30 years, largely as a result of medico-technological advances, particularly in the area of neonatal survival.
In 16 countries (14 of which are in Africa) current levels of under-5 mortality are higher than those observed in 1990. In nine countries (eight of which are in Africa) current levels exceed even those observed over two decades ago. HIV/AIDS has played a large part in these reversals.
Analyses from the demographic and health surveys show that, while child mortality has increased in many of the African countries surveyed, the gap between poor and non-poor populations has remained constant over time in this setting. In contrast, there has been a widening of the mortality gap between poor and better-off groups in the Americas, where overall child mortality rates have fallen. This indicates that survival gains in many regions have benefited the better-off. The reduction in child mortality has been much slower in rural areas, where poor people are concentrated, than in urban areas (6). These analyses suggest that health interventions implemented in the past decade have not been effective in reaching poor people.
Losses in child survival in the countries described above are at odds with impressive gains in some African countries. Despite the ravages of the HIV/AIDS epidemic in Africa, eight countries in the region have reduced child mortality by more than 50% since 1970. Among these are Gabon, the Gambia and Ghana.
Overall, at least 169 countries, 112 of them developing countries, have shown a decline in child mortality since 1970. Some of these are presented in Figure 1.7. Oman has had the most striking reduction, from 242 per 1000 live births in 1970 to its current rate of 15 per 1000 live births, which is lower than that of many countries in Europe. Overall, the lower mortality countries of the Eastern Mediterranean Region experienced an impressive decline in child mortality, which has been accompanied by a reduction in the gap between countries' child mortality levels since 1970.
Child mortality has also declined substantially in the Americas. The most striking proportional reductions in mortality have been seen in Chile, Costa Rica and Cuba, where child mortality has decreased by over 80% since 1970. There have also been large absolute reductions in child mortality in Bolivia, Nicaragua and Peru. In contrast, Haitian child mortality rates are still 133 per 1000: almost double the mortality rate of Bolivia, the next highest country in the Americas.
An interesting pattern of child mortality trends has been observed in several eastern European countries. Here, child mortality initially increased or remained constant during the 1970s, only to decline after 1980 (7). This may to some extent be attributed to a more complete registration of child and infant deaths during that period. Interestingly, while adult mortality levels increased in the early 1990s, child mortality continued to decline. There is no other region where this particular pattern of mortality has occurred in such a systematic manner, and the reasons for the trend remain poorly understood.
Causes of death in children
Infectious and parasitic diseases remain the major killers of children in the developing world, partly as a result of the HIV/AIDS epidemic. Although notable success has been achieved in certain areas (for example, polio), communicable diseases still represent seven out of the top 10 causes of child deaths, and account for about 60% of all child deaths. Overall, the 10 leading causes represent 86% of all child deaths (see Table 1.1).
Many countries of the Eastern Mediterranean Region and in Latin America and Asia have partly shifted towards the cause-of-death pattern observed in developed countries. Here, conditions arising in the perinatal period, including birth asphyxia, birth trauma and low birth weight, have replaced infectious diseases as the leading cause of death and are now responsible for one-fifth to one-third of deaths. Such a shift in the cause-of-death pattern has not occurred in sub-Saharan Africa, where perinatal conditions rank in fourth place. Here, undernutrition, malaria, lower respiratory tract infections and diarrhoeal diseases continue to be among the leading causes of death in children, accounting for 45% of all deaths.
About 90% of all HIV/AIDS and malaria deaths in children in developing countries occur in sub-Saharan Africa, where 23% of the world's births and 42% of the world's child deaths are observed (see Box 1.2). The immense surge of HIV/AIDS mortality in children in recent years means that HIV/AIDS is now responsible for 332 000 child deaths in sub-Saharan Africa, nearly 8% of all child deaths in the region.
Box 1.2 The African crisis of child mortality
There are 14 countries in WHO's African Region in which child mortality has risen since reaching its lowest level in 1990. About 34% of the population under five years of age in sub-Saharan Africa is now exposed to this disturbing trend. Only two countries outside Africa observed similar setbacks in the same period -- countries that experienced armed conflict or economic sanctions. Eight of the 14 countries are in southern Africa, which boasted some of the most notable gains in child survival during the 1970s and 1980s. Those promising gains have been wiped out in a mere decade.
The surge of HIV/AIDS is directly responsible for up to 60% of child deaths in Africa, as illustrated by the causes of child deaths in Botswana shown in the figure.
The indirect effects of HIV/AIDS in adults contribute to the tragedy. Children who lose their mothers to HIV/AIDS are more likely to die than children with living mothers, irrespective of their own HIV status. The diversion of already stretched health resources away from child health programmes into care of people living with AIDS further compounds the situation, in the presence of increasing malaria mortality, civil unrest or social anarchy.
Some progress has been observed in the areas of diarrhoeal diseases and measles. While incidence is thought to have remained stable, mortality from diarrhoeal diseases has fallen from 2.5 million deaths in 1990 to about 1.6 million deaths in 2002, now accounting for 15% of all child deaths. There has also been a modest decline in deaths from measles, although more than half a million children under 5 years of age still succumb to the disease every year (8). Malaria causes around a million child deaths per year, of which 90% are children under 5 years of age. In this age group the disease accounts for nearly 11% of all deaths (see Table 1.1).
The overall number of child deaths in India has fallen from approximately 3.5 million in 1990 to approximately 2.3 million in 2002. This impressive decline is a result of a reduction in overall child mortality rates of about 30%, and a decline in total fertility rates of around 10%. The cause-of-death pattern has remained fairly stable, with the exception of perinatal conditions whose proportion has notably increased. There were some declines in the proportion of deaths from diarrhoeal diseases, measles and tetanus, which may be the result of increased use of oral rehydration therapy and improved coverage of routine vaccination, as well as intensive immunization campaigns.
A similar picture is emerging in China, where the number of child deaths has decreased by 30% since 1990, owing to a reduction in child mortality of 18% and a 6% decline in total fertility. As in India, the most notable change in the cause-of-death pattern in China over the past decade is an increase in the proportion of perinatal deaths.
The challenge of reducing child mortality is widely recognized and effective interventions are available. The issue now is urgent implementation. The adult mortality challenges are more complex, as described in the next section.