Abstract
OBJECTIVES: To compare the global burden of myocardial disease (MD) and ischemic heart disease (IHD) attributable to high and low temperatures, and to examine demographic and socio-economic disparities over time. METHODS: We analyzed disability-adjusted life years (DALYs) and mortality for MD and IHD attributable to high and low temperatures, stratified by sex, age, region, and socio-demographic index (SDI). Decomposition analysis quantified the contributions of population growth, aging, and epidemiological changes. Projections were generated using an age-period-cohort model. RESULTS: Between 1990 and 2021, high temperature-related MD and IHD burdens increased [Estimated Annual Percent Change (EAPC): +1.26 and +1.68%, respectively], whereas low temperature burdens declined (EAPC: -1.87 and -1.73%) but remained considerably higher overall. MD disproportionately affected children under five and adults over 80, while IHD rarely appeared under 30 yet rose markedly from midlife onward. Heat-related MD and IHD burdens rose with SDI < 0.5 and declined above 0.5; cold-related burdens decreased consistently above SDI 0.75 but varied irregularly below this threshold. Central Asia exhibited the greatest heat- and cold-related burdens for both MD and IHD, whereas North Africa and the Middle East were particularly susceptible to heat. Population growth primarily fueled heat-related burdens, whereas cold-related burdens were more driven by aging and population change. Projections to 2040 indicate continuing increases in heat-related burdens, potentially exacerbating health disparities. CONCLUSIONS: Heat-attributable IHD is the fastest-growing threat, while MD remains critical for very young and older adult populations under extreme temperatures. Disparities across age, SDI, and geography highlight the urgency for targeted interventions.