Heatstroke Is Associated with an Increased Risk of Chronic Headache: A Retrospective Cohort Study

Background: Heatstroke is the most severe form of heat-related illness. It is characterized by an elevated core body temperature and central nervous system dysfunction. The aim of this study was to investigate the association between heatstroke and subsequent migraine development. Methods: This retrospective cohort study used data from the Disease Analyzer database (IQVIA) and included individuals diagnosed with heatstroke, as well as propensity score-matched individuals without heatstroke. Data about these individuals was recorded in 1216 general practices in Germany between January 2005 and December 2023. Five-year cumulative migraine incidence was assessed using Kaplan–Meiercurves, and univariable Cox regression analysis was performed to evaluate the association between heatstroke and migraine. Results: The study included 5794 individuals with heatstroke and 28,970 matched controls without heatstroke (median age: 30 years, 31–32% female). Most heatstroke cases were documented in June (32–34%), followed by July (30%), August (15–17%), and May (13%). Within five years of follow-up, 8.8% of patients with heatstroke and 4.0% of controls were diagnosed with migraine. The regression analysis revealed that heatstroke was significantly associated with an increased risk of migraine in the total population (HR: 2.26; 95% CI: 2.00–2.57), as well as in women (HR: 2.33; 95% CI: 1.96–2.79) and men (HR: 2.26; 95% CI: 1.89–2.70). Conclusion: This study highlights an important, yet previously underrecognized, association between heatstroke and an increased risk of migraine. As global temperatures continue to rise, public health strategies should focus not only on the acute prevention and management of heat-related illnesses, but also on their potential long-term neurological consequences.