Geography and Demographics
Approximately one-quarter of the global burden
of disease (GBD) can be attributed to
environmental risk factors. More than 40% of
this burden falls on children younger than
5 years (WHO 2002b). The Southeast Asian
region includes 10 countries with a total population
of approximately 1.5 billion, of whom
180 million are 0–4 years old and 614 million
are younger than 18 years. The Western
Pacific region includes 34 countries with a
total population of approximately 1.7 billion,
with 132 million children 0–4 years of age,
and 507 million persons younger than
18 years. Together, these two regions contain
53.1% of the world’s population and 52% of
the world’s children (Table 1). Infant mortality
rates and calculated life expectancy at birth
vary widely in nations across these regions,
reflecting different levels of economic and
public health development (Table 2).