HOUSTON — The incidence of stroke is rising in young adults, coinciding with an increase in traditional vascular risk factors and substance use, while stroke at older ages tend to be dropping, according to a recent study. Previous research has found that the trend is international, especially in higher-income countries.
The study published in Neurology aimed to characterize the incidence rates, 30-day case fatality rates and the burden of stroke risk factors over time in young adults from 1993 to 2020 in the Greater Cincinnati/Northern Kentucky Stroke Study.1
The study was led by the University of Cincinnati in Ohio and included participation from the Houston and Ann Arbor, MI, VAMCs.
In young adults, stroke can lead to premature death and years lived with disability. Recent studies have found a rise in stroke-related mortality among young adults, with geographic, sex and race-based disparities. Stroke-related mortality can be affected by changes in either stroke incidence rate or case fatality rates. Previous studies have found that stroke-related mortality is mainly the result of a rising incidence rate, but contemporary data is lacking in representative populations of the United States, the investigators explained.
In this study, the researchers used data from the Greater Cincinnati/Northern Kentucky Stroke Study (GCNKSS), a long-running population-based study in the five-county region of southern Ohio and northern Kentucky that is representative of the U.S. population in terms of age, percentage of Black race, education and income. Stroke in the young was defined as strokes occurring in individuals who were 20 to 54 years old. Incidence rates were generated using U.S. Census data standardized to the 2010 population. The investigators used statistical analyses to test trends and evaluate temporal trends in 30-day case fatality rates.
The 30-day case fatality rate was assessed for all patients using data from both the medical record and the National Death Index, which captures all deaths (in-hospital and out-of-hospital) in the territorial U.S. All causes of death were included.
The study reported that there were 2,076 first-ever strokes in young adults and that those patients were more likely to have hypertension, diabetes, atrial fibrillation and substance use over time. Among individuals with substance use, rising marijuana use accounted for much of the increase in stroke incidence.
The researchers also determined that the incidence rate of stroke in young adults increased from 33.90 cases/100,000 person-years in 1993 to 1994 to 62.18 cases/100,000 person-years in 2020. Meanwhile, the stroke incidence rate declined in older adults from 618.78 cases/100,000 person-years in 1993 to 1994 to 453.04 cases/100,000 person-years in 2020.
The rise in stroke incidence in younger adults appeared to be driven by ischemic stroke, with the incidence rate almost doubling from 23.8 cases/100,000 person-years in 1993 to 1994 to 47.3 cases/100,000 person-years in 2020. In addition, the study authors pointed to a modest decline in the 30-day case fatality rates in young adults (11.7% in 1993 to 1994 to 9.4% in 2020), which was driven by intracerebral hemorrhage (27.5% in 1993 to 1994 to 21.2% in 2020) and subarachnoid hemorrhage (27.9% in 1993 to 1994 to 18.6% in 2020).
Linxin Li, MD, MSc, DPhil, an associate professor and senior clinical research fellow at University of Oxford in the UK, discussed the age specific divergence for stroke incidence—strokes at younger ages increasing, while strokes at older ages are declining—with U.S. Medicine. Li wasn’t involved in the current study but co-authored a review in the International Journal of Stroke earlier this year on stroke in young and middle-aged adults.2
“This increase also coincided with increase in known stroke risk factors, including high blood pressure and diabetes. What is perhaps most alarming is that the prevalence of recreational drug use increased from less than 5% in the 1990s to greater than 40% in 2020. This really highlights where the direction of prevention should focus on as the next steps,” Li explained.
As strokes at younger ages are continuing to increase, Li suggested that the trend of more patients presenting with stroke at younger ages will continue. She said the current study underscored that clinicians should stay vigilant and shouldn’t disregard stroke-like symptoms for younger patients. On the other hand, she added, the authors also provided up-to-date estimates on short-term outcomes, which are very useful for service planning, as well as for patient consultation.
The authors of the Neurology study noted the worrisome trend of a rise in stroke incidence in young adults but also pointed to the promising, but modest decline in 30-day case fatality rates. They suggested the rise in stroke in young adults highlights the ongoing importance of primary prevention and also the importance for primary-care providers to identify and treat vascular risk factors aggressively in this group to reduce the risk of stroke, adding that the increase “coincides with a rise in both traditional vascular risk factors and substance use.”
