Stroke is usually caused by high blood pressure and other traditional risk factors. But when adults under 35 have a stroke, migraines and other non-traditional risk factors may be more likely to blame, a new study finds.

High risk decreases with age, according to a study published Tuesday in the American Heart Association journal Circulation: Cardiovascular Quality and Outcomes.

“While there are many studies demonstrating the link between migraine and stroke, to our knowledge this study may be the first to show how much of the risk of stroke is due to migraine. ,” lead author Dr. Michelle Reppert said in a news release. . Reppert is an assistant professor of neurology at the University of Colorado School of Medicine in Aurora.

Traditional risk factors for stroke include high blood pressure, high cholesterol, type 2 diabetes, smoking, obesity, physical inactivity, alcohol abuse, and heart disease. However, previous studies have shown that strokes are increasing among young adults who do not have these risk factors, and that women under 45 are more likely to have strokes than men, despite having lower rates of traditional risk factors. It has been shown to have a high incidence.

“We wanted to understand which risk factors contribute most to stroke risk in young adults,” Reppert said.

She and her colleagues analyzed health insurance claims data from more than 2,600 people in Colorado who had a stroke and more than 7,800 who did not, to determine which risk factors were most strongly associated with stroke. The study included people between the ages of 18 and 55. Most strokes are ischemic and occur when a blood vessel to the brain becomes blocked by a blood clot.

Among people aged 45 to 55 years, nontraditional risk factors were responsible for 28% of strokes in women and 19% of men. However, nontraditional risk factors were significantly associated with stroke incidence among adults aged 18 to 44, with the association strongest among those younger than 35. Nontraditional risk factors included migraines, blood clotting disorders, kidney failure, autoimmune diseases, and cancer.

In people under 35 years of age, non-traditional risk factors were associated with stroke in 43% of women and 31% of men. Although migraine topped the list, accounting for nearly 35% of strokes in women and 20% in men, migraine’s contribution to stroke risk decreased with age. Traditional risk factors in the under-35 age group were associated with 33% of strokes in women and 25% in men.

Traditional risk factors in adults aged 35 to 44 contributed to 40% of strokes in women and 33% in men. Hypertension has traditionally been the most important risk factor, and its importance increases as we age. Among adults aged 45 to 55, stroke was the cause of 27% of strokes in women and 28% of men.

Researchers were surprised to find that nontraditional risk factors, particularly migraine, play a large role in the development of stroke in young adults, Reppert said.

“The younger you are at the time of stroke, the more likely nontraditional risk factors are to cause stroke,” she said. “Developing targeted interventions requires a deeper understanding of the mechanisms underlying these non-traditional risk factors.”