Association of ABO blood group and P. falciparum malaria related outcomes: A cross-sectional study in Ethiopia

Studies elucidate conflicting results about the relationships between ABO blood groups and Plasmodium infection outcomes in humans. This study examined association between ABO blood group and Plasmodium falciparum (P. falciparum) malaria related outcomes among 1065 malaria suspected febrile patients who attended Dore Baafano Health Center, southern Ethiopia, between December, 2010 and February, 2011. Blood specimens were collected and examined for malaria using Giemsa-staining, while stool specimens were examined for helminth infections using Kato-Katz method. Haemoglobin level and blood group were determined using hemocue machine and antisera hemagglutination test, respectively. Clinical data were also collected for the patients. Among the study participants, the proportion of O, A, B and AB blood groups were 40.1%, 30.1%, 29.0% and 14.3%, respectively, and P. falciparum malaria cases in the corresponding blood groups were 14.8%, 14.0%, 13.4% and 15.7%. The odds of non-severe P. falciparum malaria were not significantly different between individuals of blood group A versus O or B versus O or AB versus O. Mean haemoglobin concentration was significantly lower in P. falciparum infected blood type A individuals compared to P. falciparum infected blood type O (β = −1.25, 95% CI = −2.31 to −0.19) or non-A (β = −1.27, 95% CI = −2.23 to −0.32) individuals. The odds of P. falciparum malaria related anaemia was about three times higher in individuals with blood type A compared to those with blood type O (adjusted OR = 2.82, 95% CI = 1.05–7.56) or non-A individuals (adjusted OR = 2.84, 95% CI = 1.15–7.01). However, mean P. falciparum density did not significantly differ among patients according to their blood groups. In conclusion, individuals with blood group A had higher risk of anaemia compared to those with O and non-A phenotypes among P. falciparum malaria patients. However, there is a need to investigate the mechanism.