Sickle cell disease in Africa: a neglected cause of early childhood mortality

Abstract

Sickle cell disease (SCD) is common throughout much of sub-Saharan Africa, affecting up to 3% of births in some parts of the continent. Nevertheless, it remains a low priority for many health ministries. The most common form of SCD is caused by homozygosity for the β-globin S gene mutation (SS disease). It is widely believed that this condition is associated with very high child mortality, but reliable contemporary data are lacking. We have reviewed available African data on mortality associated with SS disease from published and unpublished sources, with an emphasis on two types of studies: cross-sectional population surveys and cohort studies. We have concluded that, although current data are inadequate to support definitive statements, they are consistent with an early-life mortality of 50%-90% among children born in Africa with SS disease. Inclusion of SCD interventions in child survival policies and programs in Africa could benefit from more precise estimates of numbers of deaths among children with SCD. A simple, representative, and affordable approach to estimate SCD child mortality is to test blood specimens already collected through large population surveys targeting conditions such as HIV, malaria, and malnutrition, and covering children of varying ages. Thus, although there is enough evidence to justify investments in screening, prophylaxis, and treatment for African children with SCD, better data are needed to estimate the numbers of child deaths preventable by such interventions and their cost effectiveness.

Figure 1

Map of the distribution of the β^S gene in Africa Note: The map is based on representative indigenous population samples and is adapted from Figure 1b in Piel et al. The figure shows the global distribution of the sickle cell gene and geographic confirmation of the malaria hypothesis.

Figure 2

Prevalence of Hb SS by age among children in three African studies Note: The studies are Fleming et al. (Garki, Nigeria), Williams et al. (Kilifi, Kenya), and Barclay (Zambia). Hb SS, sickle cell anemia