Researchers at the Hebrew University in Jerusalem announced Thursday that they had found evidence that overweight in adolescence can lead to reduced brainpower in midlife, especially among those who come from lower-income families.
The full results from the research, carried out by the Hebrew University’s Hadassah Braun School of Public Health and Community Medicine, are to be published in the Journal of Alzheimer’s. Scientists believe the findings are especially significant due to evidence that reduced cognitive function in midlife can lead to dementia in old age.
To conduct the study, the team tracked the height and weight of a group of 507 individuals over a 33-year period, starting at the age of 17. When the participants reached the ages of 48-52, their socioeconomic position was evaluated and they were asked to complete a cognitive assessment.
Researchers reported a link between body mass index — a measure of a person’s weight compared to their height — in youngsters and their cognitive skills decades later. A higher BMI during adolescence, indicating an overweight body, they found, can impact how a person’s brain functions when they are much older, even if their weight — and BMI — changes.
“We found that higher BMI in late adolescence and the long-term cumulative burden of BMI predicted poorer cognitive function later in life,” said senior researcher Jeremy Kark. “Importantly, this study shows that an impact of obesity on cognitive function in midlife may already begin in adolescence, independently of changes in BMI over the adult life course.”
While previous research has identified a link between a person’s childhood and how smart they grow up to be, the Israeli research pinned down a specific early influence that being overweight has on those who grow up in lower socioeconomic households.
“Our results are consistent with the hypothesis that childhood living conditions, as reﬂected also by height, inﬂuence cognitive function later in life; however, our study is unique in showing that an adverse association of higher BMI with cognitive function appears to begin in adolescence and that it appears to be restricted to adults with lower childhood socioeconomic position,” Kark noted.
The study also saw indications that tall people are smarter and that women — but not men — who have a growth spurt in late adolescence gain a brain boost.
“Our results also show that taller stature was associated with better global cognitive function, independent of childhood and adult socioeconomic position, and that height increase in late adolescence, reﬂecting late growth, conferred a protective effect, but among women only,” said doctoral student Irit Cohen-Manheim, the lead author for the paper.
“Evidence for the association between impaired cognitive function in midlife and subsequent dementia supports the clinical relevance of our results,” she continued. “Findings of the relation of BMI in adolescence with poorer midlife cognitive status, particularly in light of the ongoing epidemic of childhood obesity, require conﬁrmation.”