Heat Index Exposure and Cardiovascular Disease Burden in India: Population-Attributable Risk and Economic Implications

Abstract Background Climate change is intensifying heat exposure in South Asia, yet the population-level cardiovascular disease (CVD) burden attributable to Heat Index (HI) exposure in India remains unquantified. Methods We analyzed state-level panel data (29 states, 2011–2021) linking ERA5-derived HI metrics with Global Burden of Disease CVD outcomes (DALYs, YLL, YLD). Log-linear fixed-effects panel regression models estimated the percent change in CVD burden per unit increase in HI, adjusting for state and year fixed effects. The population-attributable fraction (PAF) was calculated using a model-based counterfactual approach with the 80th percentile of observed HI as the reference threshold. State-specific economic burden was estimated by multiplying attributable DALYs by cost-per-DALY values and projected to 2030 using ARIMA and 3% annual cost growth. Results A one-unit increase in the 97.5th percentile of average HI was associated with a 1.62% (95% CI: 0.67%, 2.57%) increase in CVD DALYs and a 1.7% (0.7%, 2.7%) increase in YLL. The PAF at the 80th percentile threshold was 0.28%, corresponding to approximately 206,000 attributable DALYs in 2021 and an economic burden of approximately INR 1,485 Crore (~ USD 199 million). By 2030, the projected economic burden was approximately INR 2,174 Crore (~ USD 292 million), a 46% increase. Conclusions Extreme HI exposure is associated with a measurable fraction of India’s CVD burden that translates to a substantial and growing economic cost. These state-level estimates can inform the prioritization of heat–health interventions in India.