Risk Factors for Ischemic Stroke in Younger Adults

A Focused Update

Mary G. George, MD, MSPH, FACS


Stroke. 2020;51(3):729-735. 

In This Article

Epidemiology of Stroke in Younger Adults

The Greater Cincinnati Northern Kentucky Stroke Study—a population-based epidemiological study—found that between 1993/1994 and 2005, the mean age of those who have a stroke declined by 2 years, while the proportion of stroke among those 20 to 54 years of age increased by ≈50% from 12.9% to 18.6%. This increase was significant among both blacks and whites and was primarily seen in ischemic stroke.[8] Several other studies have documented recent increases in stroke among younger adults including the Dijon Stroke Registry, studies from the US National Inpatient Sample, the Swedish National Inpatient Register, and the Danish National Patient Register. Increases vary depending on the methodology and data source, including whether incidence rates or hospitalizations are reported, age ranges reported, and by individual stroke subtype. Most studies referenced above found increases primarily in ischemic stroke.[8–10,15,16] The Helsinki Young Stroke Registry noted relatively low stroke rates under the age 40 with sharp increases beginning at age 40. The Helsinki Young Stroke Registry also noted that overall, among ages 45 to 49 years, men outnumbered women, but among ages 15 to 30 years, women outnumbered men.[17] Other studies also noted an increase around age 40 to 45 years, after which large vessel atherosclerosis was a more dominant pathogenesis.[18]

Classification of Ischemic Stroke Subtypes

Risk factors for ischemic stroke in younger adults are not unique to younger adults and overlap considerably with those of older adults but do vary in terms of the percent contribution to ischemic stroke subtypes. When considering the TOAST[5] classification, the most common types of ischemic stroke in older adults are large artery atherosclerosis and small-vessel occlusions, while these 2 subtypes account for only 10% to 20% of stroke in younger adults.[1,3,17,19] Studies of stroke subtypes have reported a broad range and a somewhat higher prevalence (20%–47%) of cardioembolism among younger stroke patients compared with all ischemic stroke patients (20%–25%).[1,3,17,19] Of the more traditional risk factors that are highly prevalent among older adults (hypertension, dyslipidemia, and diabetes mellitus), clinical case studies and administrative studies have found that these risk factors are also highly prevalent among younger adult stroke patients although smoking is even more prevalent among younger stroke patients compared with older adults.[8,9]