Studying changing patterns in stroke incidence is essential since strokes represent a burden for public health. The aim of our study was to evaluate the epidemiological trend of strokes from 2008 to 2018 in the population-based Brest Stroke Registry (BSR) focusing on patients under 60.

All first-ever-stroke, patients aged 15 and older, with imaging, in the Pays-de-Brest from January 1st 2008 to December 31st 2017 were included. Cumulative incidence was calculated, by periods of two years, and temporal trends were evaluated by age group, sex, stroke subtype (ischemic or hemorrhagic) using a Poisson regression. Trends in stroke variables were specifically studied for young people. Ischemic stroke mechanism subtypes were analysed according to TOAST and SSS-TOAST classifications.

Over a 10-year study period, there were 6043 first-ever-strokes: 738 intracerebral hemorrhage (ICH) and 5305 ischemic strokes (IS). Mean age was 73.55±14.25years, 82.2% were older than 60 and 51.8% were women. IS incidence increased in young people from 30.4 [95% CI: 27.4; 33.8] to 37.3 [95% CI: 33.9; 41.0] per 100,000 inhabitants (P=0.0025). IS incidence≥60 decreased except for last studied period. ICH remained stable for older people but decreased in young from 5.6 [4.3; 7.1] to 2.8 [2.0; 4.0] per 100,000 inhabitants (P=0.0250). Under 60, the main risk factors were smoking (68.6%); hypertension (27.8%); high-alcohol intake (24.4%) and dyslipidemia (21%). Most IS were minor. Work-up in the IS young population was for the large majority brain magnetic resonance imaging (MRI) (74.5%); cardiac monitoring (80%): echocardiography (83.5%); and imaging of the neck vessels (89.9%). Among IS, 19.8% were taking antihypertensive drugs and 10.9% statins. According to the TOAST classification, there were 46.7% cryptogenic strokes, which was reduced to 25.5% for other cryptogenic strokes, and 2.3% for cryptogenic embolism according SSS-TOAST classification. In IS, risk profiles, clinical parameters and prior-stroke treatments did not significantly change. Dyslipidemia and use of statins were fluctuant. Diagnostic work-up improved but the frequencies of IS mechanism subtypes remained stable.

IS incidence increased while ICH incidence declined in young people. Major use of MRI may have contributed to the IS trend. The traditional risk factors studied remained stable and did not explain the increase in IS incidence. Improvement in diagnostic work-up did not lead to any change in subtypes of stroke mechanisms. Using the SSS-TOAST classification reduced the rate of cryptogenic strokes. The role of non-traditional risk factors may be explored in an attempt to explain increased incidence.