An ecological analysis of the association between human development index and malaria and dengue incidence across Indian States

Human Development Index (HDI), integrating life expectancy, education, and income, reflects societal progress and population health. Vector-borne diseases, a major public health challenge, may vary according to socioeconomic and environmental contexts. To examine the association between HDI and the incidence of malaria and dengue across Indian states during 2019–2022. State-level HDI data were obtained from the Global Data Lab, while disease incidence and population data were sourced from the National Centre for Vector Borne Diseases Control. Given limited within-state variation in HDI, analyses focused on between-state comparisons using population-averaged negative binomial regression adjusted for year, rainfall, temperature, humidity, and percent urban population. HDI was negatively correlated with malaria incidence (ρ = −0.39; p = 0.017) and positively correlated with dengue incidence (ρ = 0.61; p < 0.001). In regression analyses, HDI was not significantly associated with malaria incidence in the primary analysis (aIRR = 0.92; 95% CI 0.80–1.06; p = 0.246). Sensitivity analysis excluding outlier state demonstrated a significant inverse association (aIRR = 0.82; 95% CI 0.70–0.96; p = 0.013). For dengue, HDI was positively associated with incidence in year- and climate-adjusted models, but the association was attenuated after adjustment for urbanization (aIRR = 1.06; 95% CI 0.94–1.20; p = 0.343). However, sensitivity analysis excluding an outlier territory showed a persistent positive association (aIRR = 1.15; 95% CI 1.05–1.26; p = 0.002). These findings highlight the complex interplay of socioeconomic, environmental, and contextual factors underlying vector-borne disease patterns in India.