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 …