Introduction 10%–15% of strokes occur between 18 and 50 years old. Young stroke incidence in the UK is increasing with high risk factor burden and varied aetiology. Long-term functional and psychological sequelae are highly prevalent. This study will provide representative information on UK young strokes and develop a prognostic tool guiding primary and secondary prevention. Methods and analysis The United Kingdom Young Stroke Study (UKYSS) is an ambispective observational study of young adults aged 18–49 years with a first ever ischaemic or haemorrhagic stroke. Young strokes between 1 January 2013 and 31 December 2020 will be identified from UK stroke centres and screened for eligibility. Data will be collected on demographics, risk factors, clinical presentation, investigation, imaging, diagnosis and discharge status at baseline and survival, vascular events, epilepsy and malignancy. Patients will complete a life after stroke questionnaire to obtain current information on a variety of functional domains. Descriptive analysis will use χ 2 and Fisher’s Exact tests (if value <5) to compare categorical variables across groups and Student’s t-test or Mann-Whitney U test to compare means. Kaplan-Meier curves will measure cumulative incidences and a Cox proportional hazards model fitted to estimate the prognostic value of individual risk factors. A multivariable prognostic model for stroke recurrence and mortality will be developed and validated. Ethics and dissemination UKYSS has regulatory and ethical approval. Data will be anonymised and housed securely. Data management and confidentiality will be compliant with national regulations. Results will be submitted to peer-reviewed conferences and journals and disseminated to participants, patient organisations and local media and government organisations. Trial registration number ISRCTN11029266 .
Ferdinand et al. (Thu,) studied this question.