The researchers used weight and height data from 507 individuals tracked from over 33 years starting at age 17. The participants completed a computerized cognitive assessment at ages 48-52, and their socioeconomic position was assessed by multiple methods. Using mixed models the researchers calculated the life-course burden of BMI from age 17 to midlife, and used multiple regression to assess associations of BMI and height with global cognition.
‘Childhood household socioeconomic position appears to strongly modify the association between adolescent BMI and poorer cognition in midlife.’
In the population-based study of a Jerusalem cohort, followed longitudinally from adolescence for over 33 years, the findings point out that higher BMI in late adolescence and the long-term cumulative burden of BMI predicted poorer cognitive function later in life.
"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," said the paper's senior author, Prof. Jeremy Kark of the Hebrew University-Hadassah Braun School of Public Health and Community Medicine.
"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," added Irit Cohen-Manheim, doctoral candidate at the Braun School and lead author.
The researchers point out that while socioeconomic position may have a particularly important role in the trajectory of a person's lifetime cognitive function, it has rarely been adequately taken into account.
Prof. Kark said, "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."
"Evidence for the association between impaired cognitive function in midlife and subsequent dementia supports the clinical relevance of our results. 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," said Irit Cohen-Manheim.
- Prof. Jeremy Kark et al., Body Mass Index, Height, and Socioeconomic Position in Adolescence, Their Trajectories into Adulthood, and Cognitive Function in Midlife
, Journal of Alzheimer's Disease (2016),