Teenagers with lower levels of mental ability may be three times more likely to experience a stroke before the age of 50, research suggests.
The association held true even after taking into account a range of factors, prompting experts to say that more comprehensive assessments beyond traditional stroke risk factors are now needed to stave off disability and death.
The findings were published in the Journal of Epidemiology & Community Health.
Recent evidence suggests that strokes are becoming more common among the under-50s. About half of all survivors can expect to live with long-term physical and psychological disabilities.
Lower levels of mental ability in childhood and adolescence—including powers of concentration, problem solving, and learning—have previously been linked to higher risks of future cardiovascular and metabolic disease. But the findings were inconsistent, the researchers said.
To strengthen the evidence base, they wanted to find out whether mental ability in adolescence could be associated with an increased risk of early-onset stroke.
Researchers, led by the Gertner Institute for Epidemiology and Health Policy Research in Ramat Gan, Israel, examined data for 1.7 million young Israelis over approximately 25 years.
Before starting military service, 16- to 20-year-old Israelis undergo tests to check their eligibility. As well as weight, blood pressure and diabetes, other factors assessed included educational attainment, socio-economic background and mental ability.
The last 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.
Out of the total, 12% were recorded as having a high level of mental ability, 70% as a medium level and 18% as a low level. The participants’ results were then linked to the Israeli national stroke database.
After potentially influential factors were taken into account, those with low mental ability were more than 2.5 times more likely to have a stroke before age 50 than those with high level, while those with medium level 78% more likely to do so.
“We showed that adolescents with medium and low cognitive function had twofold and threefold increased risks, respectively, for early-onset ischemic stroke, after controlling for various confounders,” the researchers wrote.
This was an observational study, and therefore could not establish cause and effect. The researchers also acknowledged limitations to 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: “Given the increasing prevalence of early-onset stroke, the strong association between lower cognitive performance in adolescence and an increased risk of early-onset stroke highlights the need for comprehensive assessments beyond traditional stroke risk factors.
“The insights from our study suggest that cognitive performance may help identify individuals at higher risk of stroke, thereby facilitating timely interventions to address potential mediators such as health illiteracy, education and health behaviors.”
