There Is No Association Between Loiasis and Malaria: Findings from a Secondary Analysis of a Cross-Sectional Survey in Rural Gabon

Loiasis exists in regions where malaria is highly endemic, yet few studies have investigated their association as concomitant infectious diseases. Secondary data analysis from a cross-sectional survey conducted in Gabon (2015–2016) was performed to assess the association between malaria and loiasis. A total of 947 participants of all ages were enrolled in the original study. In crude analyses, malaria showed a seemingly protective association with loiasis, manifesting in an odds ratio (OR) of 0.67 (95% CI: 0.45 to 1.01; p = 0.0521). This borderline association disappeared completely after adjustment for confounders (adjusted OR: 1.31; 95% CI: 0.81 to 2.11; p = 0.276), particularly age. The apparent crude protective association is therefore likely explained by the different epidemiological distribution of both diseases according to age rather than a true biological interaction. Malaria predominantly occurred in children and loiasis mainly in older individuals. Findings of this study do not support an association between malaria and loiasis in this setting.