Reduced frequency of iron deficiency anaemia in sickle cell trait.

The prevalence and causes of anaemia among the inhabitants of a Southern Lebanese village were studied. Of the 317 patients examined 75, or 24% were found to be heterozygotes for Hb S. There was a reciprocal relation between the presence of sickle cell trait and of iron deficiency anaemia. The prevalence of iron deficiency anaemia defined as the coexistence of Hb below 13 g/dl in adult males and below 12 in adult females and children with two laboratory indicators of iron deficiency, was 10.3% in the normal population as against 1.3% in the sickle cell trait group (P less than 0.008). The reduced frequency of iron deficiency anaemia in sickle cell trait may be explained by increased iron absorption, or alternatively by reduced iron requirements and a lower risk of discrepancy between iron supply and demand. Because of the central role of iron in the function of a great number of enzymes and proteins, it is possible that protection against iron deficiency anaemia by the sickle cell trait may result in improved working capacity and a lower incidence of infections.