Demography, sanitation and previous disease prevalence associate with COVID-19 deaths across Indian States.

The severity of COVID-19 has varied across regions, with a disproportionately higher case-fatality ratio in developed nations. In India, states with higher income have reported more COVID-19 related deaths compared to lower-income states. Understanding the underlying factors such as demographics, disease burden, urbanization, and sanitation can help in designing better public health policies to mitigate future pandemics. The objective of this study is to identify key predictors of COVID-19 mortality across Indian states by examining the role of disease prevalence, demographics, urbanization, and sanitation. We analysed data from the Global Burden of Diseases India 2019 and the National Health Profile 2019, correlating them with COVID-19 mortality during two peak periods of the pandemic. Spearman correlation analysis and multivariate regression models were employed to determine significant associations and build predictive models for COVID-19 deaths. Our analysis showed a positive correlation between COVID-19 mortality and demographic factors such as the percentage of the elderly population (ρ = 0.44, p < 0.05 for the first peak; ρ = 0.46, p < 0.05 for the second peak). Urbanization was also significantly associated with higher mortality (ρ = 0.71, p < 0.05 for the first peak; ρ = 0.57, p < 0.05 for the second peak). Additionally, the prevalence of autoimmune diseases and cancer correlated positively with deaths. An unexpected finding was the positive correlation between improved sanitation (e.g., closed drainage systems and indoor toilets) and COVID-19 mortality. The best-fit multivariate regression model, combining demographics, sanitation, autoimmune diseases, and cancer, achieved an adjusted R of 0.71 for the first peak and 0.85 for the second peak. Our findings suggest that as states become wealthier, they undergo urbanization and infrastructural improvements, including better sanitation. However, these changes may also be associated with a rise in autoimmune diseases and cancer, potentially reducing immune resilience to emerging infections. This study provides novel insights into how improved living conditions and lifestyle changes may paradoxically contribute to increased COVID-19 mortality. By emphasizing the role of immune training in pandemic preparedness, our research offers a new perspective on public health strategies for mitigating future infectious disease outbreaks.