1.3 The Growth of School-Age Children The physical growth of
schoolchildren aged six to nine years of age is the result of
both environmental and genetic factors and the interaction
between these factors.42 In poor populations the main factors
affecting the physical growth of school-age children are
environmental factors experienced before puberty.43 These
include poor food consumption patterns, illness, lack of
sanitation, and poor health and hygiene practices. The potential
for catch-up growth among stunted children is thought to be
limited after age two, particularly when children remain in poor
environments.44 A recent study in the Philippines has shown that
some catch-up between the ages of two and eight and a half years
is feasible for children who were not born with low birthweight
or severely stunted in infancy.45 However, stunting at age two
years, regardless of whether catch-up was achieved or not, is
significantly associated with later deficits in cognitive
ability, further emphasizing the need to