Dose-response relationships, Plasmodium species, and trimester-specific effects of malaria on stunting in Papua, Indonesia.

OBJECTIVES: Malaria and stunting are highly prevalent in Papua, Indonesia, yet their association remains poorly understood. We examined dose-response relationships between postnatal malaria and stunting, trimester-specific prenatal effects, effect modification by insecticide-treated net (ITN) use, and risk by Plasmodium species. METHODS: Unmatched case-control study of 1301 children 12-60 months (435 cases; 866 controls) from 25 primary health centres. Exposure was ascertained from health centre registers and maternal cohort records. Multivariable logistic regression with cluster-robust standard errors was used; ITN effect modification was assessed using an interaction term. RESULTS: One postnatal malaria episode was associated with increased stunting odds [adjusted OR (aOR) 1.52; 95% CI 1.02-2.29], with a significant dose-response trend compared with no malaria exposure. Prenatal malaria was not significant after adjustment. Low birth weight was the strongest predictor (aOR 2.22; 95% CI 1.29-3.82). ITN use modified the malaria-stunting association (interaction aOR 0.37; 95% CI 0.18-0.73). Plasmodium falciparum was associated with increased stunting odds vs no prenatal malaria (OR 1.84; 95% CI 1.18-2.89). CONCLUSION: Recurrent postnatal malaria is associated with stunting in a dose-response pattern, modified by ITN use. Findings support malaria control and nutrition programme integration in endemic settings.