[tri-med] FYI - Iron deficiency and impaired child development

I am forwarding this article or URL for your information (FYI) as I believe
it may be of interest and is from a reliable source. As always, check the
information with your own doctor or health care professional before starting
or changing any treatments.

http://bmj.com/cgi/content/full/323/7326/1377

BMJ 2001;323:1377-1378 ( 15 December )

Editorials
Iron deficiency and impaired child development
The relation may be causal, but it may not be a priority for intervention

Papers p 1389


Iron deficiency affects 20% to 50% of the world's population, making it the 
most common nutritional deficiency.1 In developing
countries about half of all cases of anaemia in women and children result from 
iron deficiency, but other important and often
coexisting contributors include malaria, hookworm infestation, HIV, and 
deficiencies in other nutrients such as vitamin A and
folates. 2 3 Conversely, anaemia is just one manifestation of iron deficiency, 
and there are forms of mild to moderate iron
deficiency in which anaemia is absent but tissue function is impaired.

In children iron deficiency develops slowly and produces few acute symptoms. As 
the deficiency worsens children become pale and
weak, eat less, and tire easily. They gain weight poorly, have frequent 
respiratory and intestinal infections, and may develop pica.
The most worrying association is that between iron deficiency and impaired 
development in behaviour, cognition, and psychomotor
skills. Over the past three decades many studies have confirmed this relation, 
but whether iron deficiency is the sole cause of
these deficits remains unclear. Last year a panel of experts concluded that a 
"significant body of causal evidence exists linking
iron deficiency anaemia and child development."4 A definitive link was 
excluded, because anaemia is associated with many other
disadvantages such as poverty, low birth weight, malnutrition, poor education 
among mothers, and lack of stimulation in the homeall
of which also affect child development.

A consistent finding in different countries is that severe, chronic iron 
deficiency in infancy identifies children with poorer
cognitive function and lower scores in school achievement tests, suggesting 
that irreversible abnormalities result from a deficiency
at a critical period of growth and differentiation of the brain.5 Poorer 
function, however, may also result from psychosocial and
economic disadvantage.

How reversible, then, are these effects? A Cochrane review concluded that 
cognitive or psychomotor skills in anaemic children aged
less than 3 years failed to improve within 5-11 days of giving iron. Trials 
with longer periods of supplementation have mostly
lacked randomised placebo groups and failed to show benefits, but one of two 
small randomised studies found a clear benefit.6 In
anaemic children 3 years or older the advantages of iron supplementation are 
more convincing: six of eight double blind trials
showed benefits in measures such as achievement at school, concentration, 
efficiency, discriminant learning, short term memory, and
IQ.7

The paper by Stoltzfus et al in this week's issue (p 1389) is an important 
contribution.3 Their finding of significant improvements
in motor and language development after 12 months of supplemental iron is 
strong evidence that replenishing iron can positively
influence development even in children with severe anaemia and iron deficiency. 
The study's large sample size and double blind
design allow stronger causal inference. The paper also helps to clarify the 
contribution of anaemia and iron deficiency to
developmental delay, indicating that although iron's effect on motor 
development is mediated through improved haemoglobin
concentrations and oxygenation, development of language is promoted through 
other independent mechanisms.

What is the appropriate public health response to the high burden of anaemia 
and iron deficiency in preschool children in poor
countries? Preventing iron deficiency is the obvious response. Promoting 
exclusive breast feeding for the first six months of life
and providing appropriately fortified weaning diets is the best way forward; 
but, at best, 10% of mothers breast feed exclusively
for six months in many poor countries, and diets can improve only if poverty is 
reduced.8 Fortification of food has been successful
in developed countries but less so in the developing worldmost poor families 
cannot afford infant foods fortified with iron.
Currently, targeting pregnant women and young children for iron supplementation 
is the preferred strategy. Supplementation, however,
is costly, distribution mechanisms are often ineffective, and compliance is 
low. Furthermore, the World Health Organization has said
that, for maximum effectiveness in controlling anaemia, "integration should be 
sought with malaria prophylaxis, hookworm control,
immunisation and environmental health programmes as well as programmes for 
prevention of micronutrient malnutrition and community
based primary health care."9 Unfortunately, implementation strategies have not 
kept pace with better scientific understanding of the
disorder, and the gap between the necessary and the practical remains 
unbridged. There is no real prospect of a new generation of
smarter and stronger children, replete with iron.

Is preventing iron deficiency in children a priority in areas with few 
resources? It has recently been proposed, somewhat
idealistically, that as a minimum goal no child under two years should be 
allowed to become anaemic.10 Fortification of staple foods
(cereals, flour, sugar, salt) to deliver micronutrients to children on a large 
scale is probably the most sustainable and affordable
option, even though commitment from governments and the food industry is 
needed. Supplementation is a much less attractive
alternative, and scarce resources may be better spent on increasing coverage of 
vaccination against measles and hepatitis B,
supplying bed nets impregnated with insecticide in malarious areas, or 
improving access to nevirapine to prevent mother to child
transmission of HIV. These are tough but unavoidable choices.

Haroon Saloojee, senior lecturer.

(092sal@xxxxxxxxxxxxxxxxx)

John M Pettifor, professor.

Department of Paediatrics and Child Health, University of the Witwatersrand, PO 
Wits, 2050, Johannesburg, South Africa


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