Abstract Body (Do not enter title and authors here):
Background: Seasonal variation in aortic dissection incidence are well-documented. This study utilized a high-resolution surface temperature model and state-specific administrative medical data to investigate the relationship between long-term exposure to winter and summer temperature averages and hospitalization rates for aortic aneurysm or dissection.

Methods: Using data from the 2000-2016 State Inpatient Databases (SID), 265,795 hospitalizations with a principal diagnosis of aortic aneurysm or dissection for residents of 19 U.S. states were identified via ICD-9 and 10 codes. Daily surface temperature data, extracted from Oak Ridge National Laboratory’s Daymet weather model on a 1-km grid, were aggregated to zip codes to match SID's spatial resolution. Linear regressions, adjusted for demographics, comorbidities (including hypertension, hyperlipidemia, atherosclerosis, smoking, and genetic disorders), air pollution, and neighborhood socioeconomic status, estimated absolute changes in annual hospitalization rates associated with variations in winter and summer temperature averages. Nonlinear exposure-effect relationships were assessed using penalized cubic splines with at most nine degrees of freedom.

Results: Each Celsius degree decrease in winter and increase in summer was associated with 19.0 (95% CI: 17.5, 20.8, p<0.001) and 10.4 (95% CI: 8.0, 12.7, p<0.001) additional hospitalizations per one million person-years, respectively. These statistically significant associations were consistent across subgroups, including thoracic vs. abdominal and aneurysm vs. dissection. Further analysis revealed that cooler-than-average winter temperatures consistently correlated with increased hospitalization rates for overall aortic aneurysms or dissections and their subtypes.

Conclusion: Colder winter and hotter summer temperatures significantly increase the risk of hospitalization for aortic aneurysm or dissection. This emphasizes the importance of understanding how environmental factors contribute to aortic disease.