Proposed definition for young-onset ischemic stroke according to its cause

Young-onset stroke has a greater social impact than does stroke in older persons, indicating the importance of its prevention. Although there have been studies comparing stroke risk factors in young versus older individuals, no definition of young-onset ischemic stroke has been established. Large extracranial and intracranial atheroma, small vessel disease and atrial fibrillation have a major role in cases of stroke in the elderly, while these disorders are much less frequent in young adults. The purpose of this study was to determine the optimal cut-off point for defining young-onset ischemic stroke according to its cause.

We identified 203 patients aged 65 years or less who had been admitted to our hospital between 2010 and 2017 with ischemic stroke, and we divided them into two groups according to the causes of the stroke. We allocated patients with strokes caused by small vessel occlusion, large artery atherosclerosis, atrial fibrillation, or aortic atheroma to Group A and those with strokes of other causes to Group B which included dissection, Trousseau syndrome and cerebral sinus thrombosis. We then used receiver operating characteristics curve analysis by the above groups and by sex to determine the cut-off age for defining young-onset.

Group A comprised 131 patients (58 ± 7 years, 92 men, 39 women) and Group B 72 (45 ± 15 years, 47 men, 25 women). Receiver operating characteristics curve analysis to differentiate Group B from Group A in all participants indicated a cut-off value of 53 years of age (area under curve: 0.78 [0.71-0.85], P < 0.001), which we therefore considered should define young-onset ischemic stroke. After dividing all patients by their sex, ROC analyses identified a cut-off for age of between 53 and 54 years for men (AUC: 0.75, 95% CI: 0.65-0.85, P < 0.001). In comparison, ≤ 48 years was the cut-off for young ischemic stroke in women (AUC: 0.83, 95% CI: 0.71-0.94, P < 0.001).

The age of 53 years may be the optimal cut-off point for young-onset ischemic stroke. Of note, the cut-off point between young- and non-young-onset stroke was 48 years for women, whereas it was 53 years for men. It is therefore important to carefully examine and treat female patients with this sex difference in mind.