Abstract
This prospective cohort study explored the association between two upstream IFN-γ variants (rs2069709: G > T and rs2069705: A > G) and hazard factors for malaria outcomes in a longitudinal cohort of children (n = 941, 3-36 mos.), followed for three years. The impact of age, sex, previous malaria exposure, HIV1 infection, and sickle-cell genotypes (HbAA, HbAS, and HbSS) was also investigated. Reduced malaria episodes were associated with older age at enrollment [HR = 0.957 (95% CI = 0.953-0.961) per month, P < 2.2e-16], HIV1 infection [0.687 (0.545-0.866), P = 0.001], being female [0.910 (0.859-0.964), P = 0.040], and HbAS [0.823 (0.754-0.898), P = 0.005]. The GA/TA diplotype [0.376 (0.230-0.614), P = 0.002] also reduced the hazard of malaria, while TA haplotype increased susceptibility [1.749 (1.159-2.640), P = 0.029]. Factors protecting against the development of SMA [Hemoglobin (Hb < 6.0 g/dL)] included older age [0.927 (0.913-0.942) per month, P < 2.2e-16], previous malaria episodes [0.576 (0.542-0.614, P = 9.5e-32)], HbAS [0.553 (0.400-0.766), P = 0.015]. The rs2069705AG genotype increased the hazard of SMA [1.697 (1.002-2.875), P = 0.042]. Reduced hazard of mortality was observed for older children [0.898 (0.857-0.941), P < 2.2e-16], while a higher hazard was present in HIV-infected children [12.475 (6.380-24.392), P < 2.2e-16], and in those with HbSS [6.341 (1.944-20.686), P = 0.007]. The GG haplotype increased the mortality hazard [1.817 (0.936-3.527), P = 0.078]. The results here highlight critical factors influencing the hazard of malaria, SMA, and mortality.