α+-Thalassemia Protects against Anemia Associated with Asymptomatic Malaria: Evidence from Community-Based Surveys in Tanzania and Kenya

Abstract

Background. In hospital-based studies, α+-thalassemia has been found to protect against severe, life-threatening falciparum malaria. α+-Thalassemia does not seem to prevent infection or high parasite densities but rather limits progression to severe disease—in particular, severe malarial anemia. We assessed to what extent α+-thalassemia influences the association between mild, asymptomatic Plasmodium falciparum infection and hemoglobin concentration. Methods. The study was based on 2 community-based surveys conducted among afebrile children (0.5–8 years old; n=801) in Kenya and Tanzania. Results. Among children without inflammation (whole-blood C-reactive protein concentration ≤10 mg/L), P. falciparum infection was associated with only small reductions in hemoglobin concentration, and effects were similar across α …