Research shows that teenagers with lower mental capacity are three times more likely to have a stroke before the age of 50.
The association persisted even after a number of factors were taken into account. Experts said more comprehensive assessments than just traditional stroke risk factors are now needed to prevent disability and death.
The findings were published in the Journal of Epidemiology & Community Health.
Recent evidence suggests that strokes are becoming increasingly common among those over 50. About half of all survivors can expect to live with long-term physical and psychological disabilities.
Lower levels of mental skills in childhood and adolescence – including ability to concentrate, problem-solving and learning – have previously been linked to higher risks of future heart and metabolic diseases. But the findings were inconsistent, the researchers said.
To strengthen the evidence base, they wanted to investigate whether mental abilities during adolescence could be associated with an increased risk of early stroke.
Researchers led by the Gertner Institute for Epidemiology and Health Policy Research in Ramat Gan, Israel, examined data from 1.7 million young Israelis over a period of about 25 years.
Before entering military service, 16- to 20-year-old Israelis undergo tests to check their suitability. In addition to weight, blood pressure and diabetes, education level, socio-economic background and mental abilities were also assessed.
The final check includes tests to measure the ability to understand and carry out verbal instructions; verbal abstraction and categorization (word grouping); mathematical ability, concentration and conceptual thinking; non-verbal abstract reasoning and visual-spatial problem solving.
Of the total, 12% were scored as having a high level of mental ability, 70% as an average level, and 18% as a low level. The participants’ results were then linked to the Israeli national stroke database.
After taking into account possible influencing factors, it turned out that people with low mental capacity were more than 2.5 times more likely to have a stroke before the age of 50 than people with high mental capacity. People with average mental capacity were 78% more likely to experience this.
“We showed that adolescents with average and low cognitive function had a twofold and threefold increased risk of early-onset ischemic stroke, respectively, after controlling for several confounding factors,” the researchers wrote.
This was an observational study and therefore could not establish cause and effect. The researchers also acknowledged limitations in their findings, including the lack of information on lifestyle, such as smoking, physical activity, diet, education and important social determinants of health.
But they concluded: “In light of the increasing incidence of premature stroke, the robust association between lower cognitive performance in adolescence and increased risk of premature stroke underscores the need for comprehensive assessments that go beyond traditional stroke risk factors.
“The insights from our study suggest that cognitive performance may help identify individuals at higher risk of stroke, enabling timely interventions to address potential mediators such as health illiteracy, education and health behaviors.”