Higher temperatures are associated with increased interpersonal and self-inflicted violence-related Medicaid hospital visits in the United States

Limited evidence links short-term temperature increases to interpersonal and self-inflicted violence via physiological and behavioral pathways, especially among vulnerable communities. Here, we analyzed 14 years (1999-2012) of Medicaid claims (<i>N</i> = 332,293) for interpersonal and self-inflicted violence-related hospital visits in the United States. We compared daily hospital visits with local temperature patterns over the following six days, assessed by cause, demographics, climate region, and socioeconomic factors. We found that as heat stress rose, violence-related hospital visits also increased, especially in the first two days after higher heat stress. A 5°C increase was associated with a 1.5% [95% CI:1.1-1.9%] increase in interpersonal and a 3.7% [95% CI:1.5-5.9%] increase in self-inflicted violence visits. Though the difference across groups was not conclusive, point-estimate associations were greatest in younger individuals and ZIP Codes with higher poverty, lower educational attainment, and more non-white residents. Our results emphasize the importance of integrating mental health into heat health action plans and climate change preparedness.