Background and ObjectivesCauses of stroke in young adults differ from those in the elderly individuals, and in a larger percentage,no cause can be determined. To gain more insight into the etiology... Show moreBackground and ObjectivesCauses of stroke in young adults differ from those in the elderly individuals, and in a larger percentage,no cause can be determined. To gain more insight into the etiology of (cryptogenic) stroke in theyoung population, we investigated whether trigger factors, such as short-lasting exposure to toxins orinfection, may play a role.MethodsPatients aged 18–49 years with a first-ever ischemic stroke or intracerebral hemorrhage (ICH) in 17participating centers in the Netherlands completed a questionnaire about exposure to 9 potentialtrigger factors in hazard periods and on a regular yearly basis. A case-crossover design was used toassess relative risks (RRs) with 95% confidence intervals (95% CIs) by the Mantel-Haenszel case-crossover method, for any stroke (ischemic stroke and ICH combined) and for different etiologicsubgroups of ischemic stroke.ResultsOne thousand one hundred forty-six patients completed the questionnaire (1,043 patients withan ischemic stroke and 103 with an ICH, median age 44.0 years, 52.6% men). For any stroke, anincreased risk emerged within 1 hour of cola consumption (RR 2.0, 95% CI 1.5–2.8) and vigorousphysical exercise (RR 2.6, 95% CI 2.2–3.0), within 2 hours after sexual activity (RR 2.4, 95% CI1.6–3.5), within 4 hours after illicit drug use (RR 2.8, 95% CI 1.7–4.9), and within 24 hours afterfever or flu-like disease (RR 14.1, 95% CI 10.5–31.2; RR 13.9, 95% CI 8.9–21.9). Four triggerfactors increased the risk of other determined and cryptogenic ischemic stroke, 3 that of car-dioembolic stroke, 2 that of large vessel atherosclerosis and likely atherothrombotic strokecombined and stroke with multiple causes, and none that of stroke due to small vessel disease.DiscussionWe identified cola consumption, vigorous physical exercise, sexual activity, illicit drug use, fever, andflu-like disease as potential trigger factors for stroke in the young population and found differencesin the type and number of trigger factors associated with different etiologic subgroups of ischemicstroke. These findings might help in better understanding the pathophysiologic mechanisms of(cryptogenic) stroke in the young population. Show less