Title: The risks of iron deficiency anaemia amongst populations
Key words: iron, deficiency, anaemia, morbidity, iron depletion, infancy, prematurity, cow’s milk, breast feeding, teenage, growth spurt, girls, menorrhagia, pregnancy, fad diets, vegetarians, vitamin C, tea, coffee, milk, malabsorption, achlorhydria, hookworm, bleeding, elderly, bereaved, haematocrit, cognition, cognitive, psychomotor,
Date: Oct 2006
Category: Specific conditions
Author: Morgan, G
The risks of iron deficiency anaemia amongst populations
Worldwide, iron deficiency is the most prevalent micronutrient deficiency and has been linked to significant levels of morbidity. In developing countries it has been estimated that 30-40% of young children and premenopausal women are affected (WHO 1992). This reflects various degrees of iron depletion leading eventually to complete depletion of the iron stores and the onset of iron deficient anaemia. In developed countries the incidence of depletion is much lower due to higher levels of overall nutrition. In one US study, for example (Looker 1997), iron deficiency of around 5% was found in children aged 1-2 years, amongst whom half were clinically anaemic.
The following social groups pose the greatest concern for public health:
The very young
Due to rapid growth during infancy, iron status is not infrequently compromised with an incidence of anaemia peaking at 9-18 months of age. Prematurity, with lower initial basal iron reserves, and feeding on cows milk from birth with bleeding from the gastrointestinal tract from milk sensitisation, predispose to the condition (Ziegler 1990). Lower awareness of the benefits of breast feeding amongst poorer mothers militates against adequate iron repletion in this group.
The teenage growth spurt, particularly in girls, is often not matched by increased dietary iron intake.
This may be due to primary menorrhagia or dysfunctional bleeding, or due to the presence of an intrauterine device.
Depletion of the iron stores follow multiple or frequent pregnancies leads to anaemia.
Groups on low iron content diets
High phytate diets, characteristic of the diets of many population groups such as vegetarians and South Asian communities, are the single most common cause of iron deficiency anaemia in all age groups. Teenage girls on fad diets may fall into this category. Tea, coffee or milk taken with meals or a diet low in vitamin C reduce iron bioavailability and may be significant contributing factors.
Groups exposed to disease factors
Worldwide hookworm remains the leading cause of gastrointestinal blood- loss-mediated iron deficiency anaemia and is more prevalent in deprived social groups. In developed countries the elderly are more likely to be affected by chronic diseases involving bleeding or malabsorption of iron, e.g. from tumours of the bowel or uterus, NSAID use, achlorhydria or following gastric surgery.
Population groups at most risk are the elderly, bereaved, depressed and those suffering from alcoholism or drug misuse. Poverty, isolation, impaired mobility and lack of nutritional awareness all play their part.
The clinical effects of iron deficiency anaemia
The major pathological effects of iron deficiency anaemia relate to the following:
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