The study was published in the scientific journal Neurology Open Access (NOA).

Cryptogenic strokes remain a mystery to doctors: the cause of vascular blockage remains unknown. Symptoms include weakness, speech and vision problems, and the outcome can be fatal.

The experiment involved 546 people aged 18-49 who had suffered a stroke, and the same number of healthy people.

According to the analysis, smoking turned out to be the main risk factor. In the group of stroke survivors, 33% were smokers, compared with 15% in the control group.

After taking into account risk factors (alcohol, blood pressure, and education level), smokers were twice as likely to have a stroke. Among men, the risk increased threefold, and among people aged 45-49, it was almost four times higher. Those who smoked more than 20 packs of cigarettes a year had a 4-7-fold higher risk.

Scientists have called for increased anti-smoking measures, especially among young people, to reduce the number of strokes.