Agriculture Reference
In-Depth Information
IRon defIcIency AnemIA
Numerous studies have shown that iron deficiency anemia (IDA) in infants and chil-
dren is associated with poorer concurrent mental and motor function and behavioral
changes. These have been discussed in detail in recent reviews (Grantham-McGregor
and Ani 2001, Lozoff et al. 2006). IDA is associated with many socioeconomic fac-
tors that also affect development, so it is difficult to draw conclusions about causality
from these cross-sectional studies. Here, we focus on long-term follow-up studies of
previously anemic children and supplementation trials that provided stronger evi-
dence of the effect of IDA on child development.
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Follow-up studies have shown poorer developmental outcomes in infants and chil-
dren who experienced IDA despite treatment for IDA and adequate iron status at
follow-up. A meta-analysis estimated that for each 10 g/L decrease in hemoglobin,
subsequent IQ later in childhood was lower by 1.73 points (Stoltzfus et al. 2005). In a
population study in one county in the state of Florida, children with low hemoglobin
in infancy were more likely to have been placed in special education by age 10 years
(Hurtado et al. 1999).
The longest follow-up of IDA children was conducted in Costa Rica. In this study,
children with moderate IDA or chronic iron deficiency at age 12 to 23 months were
assessed at age 11 to 14 years and compared with children who were never iron
deficient. The previously iron-deficient children had poorer educational achievement
and motor ability and had several behavioral problems, including more anxiety and
depression, difficulties with attention, and social problems (Lozoff et al. 2000). The
children were tested again at age 19 years, and the cognitive difference between the
iron deficient and those never iron deficient had increased (Lozoff et al. 2006b).
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There have been several reports of the effects of treatment of IDA on the develop-
ment of infants and children. However, few of these have been randomized trials,
and many were of short duration (up to 2 weeks) and therefore may not have allowed
sufficient time for benefits to development to occur. These have been reviewed in
detail elsewhere (Grantham-McGregor and Ani 2001). Studies in which treatment
was given for at least 2 months have had varied results, with some showing that chil-
dren with IDA continued to have poorer development. In other studies, substantial
benefits have been reported. For example, in an Indonesian study children aged 12
to 18 months with mild-to-moderate IDA showed substantial gains in mental and
motor development after 4 months of treatment compared with untreated children
(Idjradinata and Pollitt 1993). Studies with older children have generally shown some
benefits to cognitive ability and school achievement with treatment (e.g., Soemantri
et al. 1985, Seshadri and Gopaldas 1989).
