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 accounting for a range of factors, prompting experts to say more comprehensive assessments beyond traditional stroke risk factors were now needed to ward off disability and death.
The findings were published in the Journal of Epidemiology & Community Health.
Recent evidence suggests strokes among the under-50s are becoming more common. About half of all survivors can expect to live with long-term physical and psychological impairments.
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 diseases. But the findings were inconsistent, the researchers said.
To strengthen the evidence base, they wanted to find out if mental ability in adolescence might be associated with a heightened 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 about 25 years.
Before starting military service, 16- to 20-year-old Israelis undergo tests to check their suitability. As well as weight, blood pressure and diabetes, other factors assessed included educational attainment, socioeconomic background and mental ability.
The last check includes tests to measure the ability to understand and carry out verbal instructions; verbal abstraction and categorisation (word grouping); mathematical ability, concentration and conceptual thinking; non-verbal abstract reasoning and visual-spatial problem-solving.
Out of the total, 12% were scored as having a high level of mental ability, 70% as having a medium level, and 18% as having a low level. The participants’ results were then linked to the Israeli national stroke database.
After accounting for potentially influential factors, those with low mental ability were more than 2.5 times as likely to have a stroke before the age of 50 as those with a high level, while those with a medium level were 78% more likely to do so.
“We demonstrated that adolescents with medium and low cognitive function had twofold and threefold increased risks, respectively, for early-onset ischaemic 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: “In light of the increasing incidence of early onset stroke, the robust association between lower cognitive performance in adolescence and an increased risk of early-onset stroke underscores the need for comprehensive assessments beyond traditional stroke risk factors.
“The insights from our study suggest that cognitive performance might aid in identifying individuals at higher stroke risk, thus facilitating timely interventions to address potential mediators such as health illiteracy, education, and health behaviours.”