Risk Factors for Early‐Onset Ischemic Stroke: A Case‐Control Study

BACKGROUND: Recent studies have shown an increasing prevalence of vascular risk factors in young adults with ischemic stroke (IS). However, the strength of the association between all vascular risk factors and early‐onset IS has not been fully established. METHODS AND RESULTS: We compared 961 patients with a first‐ever IS at 25 to 49 years to 1403 frequency‐matched stroke‐free controls from a population‐based cohort study (FINRISK). Assessed risk factors included an active malignancy, atrial fibrillation, cardiovascular disease, current smoking status, a family history of stroke, high low‐density lipoprotein cholesterol, high triglycerides, low high‐density lipoprotein cholesterol, hypertension, and type 1 and type 2 diabetes mellitus. We performed subgroup analyses based on age, sex, and IS etiology. In a fully adjusted multivariable logistic regression analysis, significant risk factors for IS consisted of atrial fibrillation (odds ratio [OR], 10.43; 95% confidence interval [CI], 2.33–46.77], cardiovascular disease (OR, 8.01; 95% CI, 3.09–20.78), type 1 diabetes mellitus (OR, 6.72; 95% CI, 3.15–14.33), type 2 diabetes mellitus (OR, 2.31; 95% CI, 1.35–3.95), low high‐density lipoprotein cholesterol (OR, 1.81; 95% CI, 1.37–2.40), current smoking status (OR, 1.81; 95% CI, 1.50–2.17), hypertension (OR, 1.43; 95% CI, 1.17–1.75), and a family history of stroke (OR, 1.37; 95% CI, 1.04–1.82). High low‐density lipoprotein cholesterol exhibited an inverse association with IS. In the subgroup analyses, the most consistent associations appeared for current smoking status and type 1 diabetes mellitus. CONCLUSIONS: Our study establishes the associations between 11 vascular risk factors and early‐onset IS, among which atrial fibrillation, cardiovascular disease, and both type 1 and 2 diabetes mellitus in particular showed strong associations.