Incidence of stroke among young adults is on the rise worldwide. Inequities remain among minorities and little is known about stroke characteristics among young Pacific patients. French Polynesia (FP), located in the middle of the South Pacific Ocean, could provide insight into this problem.

Patients aged 18–54years consecutively treated for first-ever acute ischemic stroke in Tahiti, FP, from January 2022 to December 2023 were compared to a reference cohort enrolled from January 2017 to July 2021 in Toulouse, France. Patients’ characteristics were recorded and cause of stroke was classified using the ASCOD (A: atherosclerosis; S: small vessel disease; C: cardiac pathology; O: other causes; D: dissection) classification system.

In total, 187 patients were included in Tahiti (Polynesians) and compared to 743 patients in Toulouse (mainland French [MF]). Median age was 47years old in both groups. Hypertension, diabetes, hyperlipidemia, obesity, atrial fibrillation and mechanical valve were significantly higher in Polynesian patients, whereas MF patients were more likely to be men, tobacco users, and to have a stroke related to a foramen oval with atrial septal aneurysm (all P<0.05). Multivariate analysis revealed higher prevalence of grade 1 (potentially causal) atherothrombotic (adjusted OR [aOR]: 1.775; 95% CI: 1.117–2.820; P=0.015) and cardio-embolic stroke in Tahiti (aOR: 2.966; 95% CI: 1.956–4.496; P<0.001), and higher rate of dissections in Toulouse (aOR: 4.545; 95% CI: 1.616–12.821; P=0.004). Cervical atherosclerosis was significantly associated with MF patients (aOR: 5.587; 95% CI: 2.326–13.514; P<0.001), and intracranial atherosclerosis with Polynesian patients (aOR: 3.257; 95% CI: 1.364–7.778; P=0.008).

Polynesian and MF young adults with stroke appeared to have widely different characteristics and cause of stroke. These disparities underscore the necessity for tailored prevention programs and therapeutic approaches that address the unique risk profile and etiological patterns observed in Pacific Islanders.