Title : Association between household wealth and malaria infection in the LLINEUP2 cluster randomized trial, Uganda (2020–2023)
Abstract:
Background: Malaria remains a major public health burden in Uganda, accounting for ~4.8% of global cases. Despite expanded vector control like long-lasting insecticidal nets (LLINs), transmission disproportionately affects socioeconomically disadvantaged populations. This study investigated the association between household wealth and malaria infection and examined whether housing quality modifies this relationship.
Methods: We conducted a cross-sectional analysis using 12-month follow-up data from the LLINEUP2 trial (32 districts, 2020-2023). The final analytic sample included 7,241 participants. Household wealth was categorized into tertiles using a multidimensional index (PCA) of assets and food security. The primary outcome was microscopy-confirmed Plasmodium infection. Housing was dichotomized into "modern" (improved materials/closed eaves) or "traditional." We used Generalized Estimating Equation (GEE) Poisson regression to estimate adjusted Prevalence Ratios (aPR), adjusting for age, sex, and bed net availability, with an interaction term for housing type.
Results: Overall malaria prevalence was 19.8%. A significant wealth gradient was observed (p < 0.0001), compared to the least poor, the middle (aPR=1.72; 95% CI: 1.40–2.13) and poorest tertiles (aPR=2.15; 95% CI: 1.70–2.73) had significantly higher prevalence. Importantly, housing type modified this association (p < 0.05). While wealth differences were modest among those in traditional housing, the disparity more pronounced in modern housing: the poorest residents had over twice the malaria prevalence of the least poor (aPR=2.30; 95% CI: 1.60-3.30; p < 0.0001).
Conclusions: Socioeconomic disparities remain a powerful driver of malaria risk despite widespread LLIN coverage. The widening wealth gap within modern housing suggests that structural improvements alone may not bridge equity gaps without addressing underlying poverty. Malaria policy should integrate housing improvements with equity-focused targeting and poverty-sensitive program design to enhance intervention effectiveness.
