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Open Access Study protocol

The Norwegian Stroke in the Young Study (NOR-SYS): Rationale and design

Annette Fromm12*, Lars Thomassen12, Halvor Naess12, Rudy Meijer3, Geir Egil Eide45, Jostein Kråkenes26, Christian A Vedeler12, Eva Gerdts78, Terje H Larsen79, Karel K-J Kuiper7, Elin Laxdal108, David Russell1112, Turgut Tatlisumak13 and Ulrike Waje-Andreassen1

Author Affiliations

1 Department of Neurology, Haukeland University Hospital, Bergen, Norway

2 Department of Clinical Medicine, University of Bergen, Bergen, Norway

3 Julius Center of Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands

4 Centre for Clinical Research, Haukeland University Hospital, Bergen, Norway

5 Department of Public Health and Primary Health Care, Lifestyle Epidemiology Research Group, University of Bergen, Bergen, Norway

6 Department of Radiology, Haukeland University Hospital, Bergen, Norway

7 Department of Heart Disease, Haukeland University Hospital, Bergen, Norway

8 Department of Clinical Science, University of Bergen, Bergen, Norway

9 Department of Biomedicine, University of Bergen, Bergen, Norway

10 Department of Vascular Surgery, Haukeland University Hospital, Bergen, Norway

11 Department of Neurology, Cerebrovascular Centre, Oslo University Hospital, Rikshospitalet, Oslo, Norway

12 Institute of Clinical Medicine, University of Oslo, Oslo, Norway

13 Department of Neurology, Helsinki University Central Hospital, Helsinki, Finland

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BMC Neurology 2013, 13:89  doi:10.1186/1471-2377-13-89

Published: 17 July 2013



Ischemic stroke in young adults is a major health problem being associated with a higher vascular morbidity and mortality compared to controls, and a stroke recurrence rate of 25% during the first decade. The assumed cause of infarction and the detected risk factors determine the early- and long-term treatment. However, for many patients the cause of stroke remains unknown. Risk factor profile and etiology differ in young and elderly ischemic stroke patients, and atherosclerosis is the determined underlying condition in 10 to 15%. However, subclinical atherosclerosis is probably more prevalent and may go unrecognized.

Ultrasound imaging is a sensitive method for the detection of arterial disease and for measurement of adipose tissue. The relationship between intima-media thickness (IMT), plaques, cardiovascular risk factors including visceral adipose tissue (VAT) and ischemic events has repeatedly been shown.

We have established The Norwegian Stroke in the Young Study (NOR-SYS) as a three-generation research program with the goal to increase our knowledge on heredity and the development of arterial disease and ischemic stroke. Extended standardized ultrasound examinations are done in order to find subclinical vessel disease for early and better prophylaxis.


NOR-SYS is a prospective long-term research program. Standardized methods are used for anamnestic, clinical, laboratory, imaging, and ultrasound data collection in ischemic stroke patients aged ≤60 years, their partners and joint adult offspring. The ultrasound protocol includes the assessment of intracranial, carotid and femoral arteries, abdominal aorta, and the estimation of VAT. To date, the study is a single centre study with approximately 400 patients, 250 partners and 350 adult offspring expected to be recruited at our site.


NOR-SYS aims to increase our knowledge about heredity and the development of arterial vascular disease in young patients with ischemic stroke and their families. Moreover, optimization of diagnostics, prophylaxis and early intervention are major targets with the intention to reduce stroke recurrence and other clinical arterial events, physical disability, cognitive impairment and death.

NOR-SYS is reviewed and approved by the Regional Committee for Medical and Health Research Ethics, Western-Norway (REK-Vest 2010/74), and registered in NCT01597453.

Ischemic stroke; Stroke in the young; Atherosclerosis; Arterial disease; Ultrasound; Heredity; Vascular risk; Long-term outcome; Mortality