Abstract TP130: The Younger Young and the Older Young: Age-Driven Patterns in Stroke-type Profiles

Background and Purpose: The interplay between age, vascular risk profile, and stroke subtype among young adults with acute ischemic stroke (AIS) is poorly characterized. We hypothesize that young patients with stroke may be separable into 1) those with early exposure to common vascular risk factors, and 2) those with less common causes of stroke, with age influencing this distinction. We compared demographics, vascular risk factors, and TOAST classification between young adults with AIS, separating them at the median age into “younger young” and “older young” groups. Methods: All consecutive patients aged 18-49 years with an acute ischemic stroke admitted to our safety-net hospital between 2013–2025 were included. We retrospectively extracted demographics features, vascular risk factors, and TOAST classification. Descriptive statistics summarized group characteristics, and chi-square tests assessed differences by age below and above the median. Results: Among 561 AIS subjects (median age 43 years, IQR 37-47, 55.0% male), those ≥43 years (n=307) had a higher prevalence of hypertension (60.9% v 31.5%, p<0.001), diabetes (32.9% v 15.0%, p<0.001), dyslipidemia (23.1% v 13.8%, p=0.01), and body mass index (p= 0.002), determined by the overweight (22.4% v 26.5%) and obesity category (16.1% v 25.1%). TOAST distribution differed between the groups (p<0.001), driven by more with small vessel disease in the older group (21.8% v 7.9%), while “other determined etiology” was less frequent in the older group (12.1% v 24.4%). Cryptogenic stroke remained the most common subtype in both groups (31.5% v 34.2%). Conclusion: These findings suggest that, among young adults with ischemic stroke, those closer to midlife (≥43 years) exhibit a more common vascular risk factor profile and greater prevalence of small vessel disease compared with their younger counterparts. In contrast, younger patients (<43 years) more often have strokes due to less common etiologies. These findings support the importance of distinguishing between the “younger young” and “older young” when evaluating stroke mechanisms and tailoring prevention strategies.