Mortality and Morbidity

Mortality and Morbidity: what are the major health problems in the developing world?

On one hand, people in low-income countries are much worse off, and much more likely to die
prematurely, than people in wealthier parts of the world. On the other hand, it’s important to
note that those who live past age five have strong chances of living to the age of 60; saving a life
from even a single cause of death means saving a person who is likely to live significantly longer.
Children under five in low-income countries primarily die of preventable and treatable diseases
such as malaria, respiratory infections, diarrhea, perinatal conditions, measles, and HIV/AIDS.
Between the ages of 5 and 60, the major causes of death in low-income countries (relative to
higher-income countries) are HIV/AIDS, tuberculosis, and maternal mortality (i.e., deaths in
childbirth). After the age of 60, there are large differences in the mortality rates for many of the
same causes of death that affect those under 5, as well as for many conditions that require
advanced medical attention (heart disease, cancer, diabetes).
The table below shows the differences between low-income and high-income countries, in
terms of deaths per 1,000, by age range and cause of death. It is color-coded: yellow squares
represent causes of death for which mortality rates are greater in low-income countries by at
least 0.5 deaths per 1,000 people, orange squares represent causes of death for which mortality
rates are greater in low-income countries by at least 1 deaths per 1,000 people), and red
squares represent causes of death for which mortality rates are greater in low-income countries
by at least 2.5 deaths per 1,000 people.
Note that conditions vary within the developing world. Mortality rates for many causes are
higher in Sub-Saharan Africa than in the group of low-income countries (which includes some
highly populous Asian countries, such as India, Pakistan, and Bangladesh).
Non-fatal health problems
Household surveys of those living on under $1 or $2 per day show that the poor are often sick.
In the surveys cited by Banerjee and Duflo (2006), in every country for which data was available
an average of over 10% of households reported at least one member needed to see a doctor in
the month prior to the survey. In many areas the average exceeded 25%; parts of India, Mexico,
and Nicaragua had averages above 35%. Here we do not discuss all health problems in detail,
but we present three prevalent conditions (malnutrition, parasitic worms, and malaria) which
are both direct causes of symptoms and risk factors for other conditions. In addition, we
present data on the prevalence of a selection of health problems that are common in lowincome
countries and compare prevalence rates in these countries to rates in high-income
Malnutrition is a widespread problem in the developing world. It is estimated that in 2000-02,
over 800 million people in the developing world were undernourished (insufficient energy
intake), and 2 billion are micronutrient deficient. In 2005, approximately 32% of children under
five in developing countries were stunted (had a height-for age that was more than two
standard deviations below the global average), which likely reflects chronic malnutrition
throughout life. Malnourishment may be both caused by disease (such as parasitic worms) and
increase susceptibility to disease. Lacking certain nutrients has been associated with a wide
range of health problems including low energy, diarrhea, anemia, hypothyroidism, poor vision,
and pneumonia. We do not know how common or severe these symptoms generally are among
malnourished people. Malnutrition is sometimes associated with infection with parasitic
worms. It is estimated that there are more than 1.2 billion roundworm infections globally, 700-
800 million infections with each hookworm and whipworm, and 250 million infections with
schistosomiasis. While most infections do not cause symptoms, heavy worm infection can
cause anemia, dysentery, and growth retardation. In the long run, worm infection “impairs
physical and mental growth in childhood, thwarts educational advancement, and hinders
economic development.”
Death from worm infection can occur, but is fairly rare. Another major cause of disability and
suffering is malaria. The Disease Control Priorities Project estimates that there were 213 million
cases of malaria in 2000, resulting in over 1.1 million deaths. This means that while malaria is a
leading cause of death, the vast majority of cases are not fatal, but do cause suffering and
disability. Like many other diseases, risk of malaria infection and complications are increased by
malnutrition. As can be seen in the chart above, children under five average over 4 days of
sickness with malaria per year, and older children fall sick every 2-3 years for an average of 2.3
days. Uncomplicated malaria is characterized by fever, headaches and nausea. Severe malaria
can cause cognitive impairment, seizures, coma, respiratory distress, and heart problems.
What problems do people in the developing world believe are most pressing?
In 2006, the Gallup World Poll asked a representative sample from 26 Sub-Saharan Africa
countries to rank the Millennium Development Goals (MDGs) in order of importance to them.
The MDGs are a set of targets established by the United Nations in 2000 on a range of human
development goals including poverty, education, health, gender equality, and the environment.
Respondents consistently ranked reducing poverty and reducing hunger as the two most
important goals. Health goals followed the top two, with reducing the spread of HIV’ ranking
third and reducing under five mortality, maternal mortality and reducing the spread of
malaria and TB coming in at 5, 6, and 8, respectively, out of a total of 12 goals. One argument
for why health goals are not ranked higher than they are, argued by Deaton (2008), is that
Africans report being more satisfied with their health than we might expect because they are
more used to being sick. The youth-focused goals of ‘Providing more jobs for youths’ and
‘Achieving primary education for all’ were also considered important by many respondents and
were ranked 4 and 7, respectively. The goals of improving access to clean water and sanitation,
achieving gender equality, and increasing access to new technology were least important to
those surveyed. Each respondent was asked to rank order six of the twelve goals. A value of 1
was assigned to the top-ranked goal, through 6 for the lowest-ranked goal. Thus the averages
below fall in the range of 1 to 6.
were few
in how
men and
urban and
Millennium Development Goal Weighted
Average Score
Reducing poverty 2.41
Reducing hunger 2.48
Reducing the spread of HIV/AIDS 3.05
Providing more jobs for youth 3.17
Reducing the death rate among children under five 3.34
Reducing the number of women dying during childbirth 3.38
Achieving primary education for all 3.62
Reducing the spread of malaria and TB 3.64
Improving access to safe drinking water 3.75
Improving access to sanitation facilities 4.09
Achieving gender equality and empowering women 4.38
Providing access to new technology 4.65
rural dwellers, employed and unemployed adults, or different age and education cohorts ranked
the goals. Rankings did vary across countries and regions, but reducing hunger and poverty
were the top two goals for all but 6 of the 26 countries polled. Of these six, four were Southern
African countries where HIV prevalence is very high; all four ranked ‘Reducing the spread of HIV’
as their top priority.