In a case-control study, atherosclerotic risk factors were uncommon in childhood and did not appear to be associated with the pathogenesis of arterial ischemic stroke in children or in early young adulthood.
But by the fourth and fifth decades of life, these risk factors were strongly associated with a significant risk for stroke, heightening that risk almost tenfold.
“While strokes in childhood and very early adulthood are not likely caused by atherosclerotic risk factors, it does look like these risk factors increase throughout early and young adulthood and become significant risk factors for stroke in the 30s and 40s,” lead author Sharon N. Poisson, MD, MAS, associate professor of neurology at the University of Colorado at Denver, Aurora, said in an interview.
The findings were published online in JAMA Neurology.
In this study, the researchers focused on arterial ischemic stroke, not hemorrhagic stroke. “We know that high blood pressure, diabetes, smoking, obesity, all of these are risk factors for ischemic stroke, but what we didn’t know is at what age do those atherosclerotic risk factors actually start to cause stroke,” Dr. Poisson said.
To find out more, she and her team did a case control study of data in the Kaiser Permanente Northern California system, which had been accumulating relevant data over a period of 14 years, from Jan. 1, 2000, through Dec. 31, 2014.
The analysis included 141 children and 455 young adults with arterial ischemic stroke and 1,382 age-matched controls.
The children were divided into two age categories: ages 29 days to 9 years and ages 10-19 years.
In the younger group, there were 69 cases of arterial ischemic stroke. In the older age group, there were 72 cases.
Young adults were divided into three age categories: 20-29 years (n = 71 cases), 30-39 years (144 cases), and 40-49 years (240 cases).
Among pediatric controls, 168 children aged 29 days to 9 years (46.5%) and 196 children aged 10-19 years (53.8%) developed arterial ischemic stroke.
There were 121 cases of ischemic stroke among young adult controls aged 20-29 years, 298 cases among controls aged 30-39 years, and 599 cases in those aged 40-49 years.
Both childhood cases and controls had a low prevalence of documented diagnoses of atherosclerotic risk factors (ARFs). The odds ratio of having any ARFs on arterial ischemic stroke was 1.87 for ages 0-9 years, and 1.00 for ages 10-19.
However, cases rose with age.
The OR was 2.3 for age range 20-29 years, 3.57 for age range 30-39 years, and 4.91 for age range 40-49 years.
The analysis also showed that the OR associated with multiple ARFs was 5.29 for age range 0-9 years, 2.75 for age range 10-19 years, 7.33 for age range 20-29 years, 9.86 for age range 30-39 years, and 9.35 for age range 40-49 years.
Multiple risk factors were rare in children but became more prevalent with each decade of young adult life.
The presumed cause of arterial ischemic stroke was atherosclerosis. Evidence of atherosclerosis was present in 1.4% of those aged 10-19 years, 8.5% of those aged 20-29 years, 21.5% of those aged 30-39 years, and 42.5% of those aged 40-49 years.
“This study tells us that, while stroke in adolescence and very early adulthood may not be caused by atherosclerotic risk factors, starting to accumulate those risk factors early in life clearly increases the risk of stroke in the 30s and 40s. I hope we can get this message across, because the sooner we can treat the risk factors, the better the outcome,” Dr. Poisson said.