Assessing Heat-Health Vulnerability Through Temporal, Demographic, and Spatial Lenses: A Time-Stratified Case-Crossover Analysis in New York State.

New York State (NYS) has experienced warming outpacing the national average, and heat events are increasing. This case-crossover study uses conditional logistic regression to estimate how maximum heat index affects heat-related illness across temporal, demographic, and spatial groups in NYS, from May to September, 2008-2019. The highest risks were in May (Relative Risk (RR) = 1.81, CI: 1.72, 1.90) and August (RR = 1.86, CI: 1.79, 1.94). Older adults, especially those aged 85 and above, are at greatest risk (RR = 1.83, CI: 1.71, 1.96). The Southern Tier climate region had a higher risk (RR = 1.93, CI: 1.80, 2.07) than several other regions. Overall, similar risk between rural and urban NYS was observed. Rural non-Hispanic Black (RR = 2.38, CI: 1.78, 3.19) populations had a higher risk than their urban counterparts. This study was innovative for NYS, providing a deeper understanding of heat-health risks to vulnerable sub-groups. This can assist with facilitating targeted interventions and public health messaging during the periods of highest risk, such as promoting awareness of cooling centers and air-conditioning benefits.