Abstract Body (Do not enter title and authors here): Background: The rising incidence of stroke among young adults is partly explained by underdiagnosis of risk factors such as hypertension. Current blood pressure cutoff values for hypertension diagnosis in adolescence are not based on cardiovascular outcomes and lack specificity for sex, even though female adolescents have lower blood pressure values.

Methods: A nationwide, population-based, retrospective cohort study including data of all Israeli adolescents (16-19 years) who were evaluated prior to mandatory military service in 1985 through 2013. The medical evaluation included routine measurements of height, weight, and blood pressure. The primary outcome was the first occurrence of a stroke at a young age (≤52 years) as documented in the National Stroke Registry. Cox proportional hazard models were applied separately for males and females and adjusted for adolescent body mass index and sociodemographic variables. Diabetes status in adulthood, as documented in the National Diabetes Registry, was also accounted. Several sensitivity analyses were conducted, including the evaluation of ischemic stroke cases only as the outcome and stroke occurrence at a very young age (≤45 years).

Results: The cohort comprised 1,897,048 adolescents (42.4% females). During 11,355,476 person-years of follow-up, there were 1,470 first stroke events, 1,233 (83.8%) cases were of ischemic etiology. In male adolescents, a diastolic blood pressure of ≥80 mmHg was associated with an adjusted hazard ratio (aHR) for stroke at a young age of 1.28 (95% confidence interval 1.05-1.58) (Image 1). In male adolescents with blood pressure of 70-79 mmHg, the aHR was comparable to that of the reference group (<70 mmHg). The aHRs of female adolescents with a blood pressure of 70-79 mmHg and ≥80 mmHg were 1.40 (1.09-1.80) and 1.39 (1.03-1.88), respectively (Image 2). In the sub-analysis of ischemic stroke cases as the outcome, the aHRs were 1.63 (1.23-2.16) and 1.59 (1.14-2.22) for females with blood pressure of 70-79 mmHg and ≥80 mmHg, respectively. The results persisted in extensive sensitivity analysis (Image 1, Image 2).
Adolescent systolic blood pressure of 120-129 mmHg or ≥130 mmHg compared to <120 mmHg was not associated with the outcome in adolescents of both sexes.

Conclusions: Diastolic blood pressure in adolescence was associated with stroke at a young age, with a lower cutoff level among females.