Combined effects of age and BMI are related to altered cortical thickness in adolescence and adulthood

Abstract

Overweight and obesity are associated with functional and structural alterations in the brain, but how these associations change across critical developmental periods remains unknown. Here, we examined the relationship between age, body mass index (BMI) and cortical thickness (CT) in healthy adolescents (n=70; 14 -19 y) and adults (n=75; 25 -45 y). We also examined the relationship between adiposity, impulsivity, measured by delay discounting (DD), and CT of the inferior frontal gyrus (IFG), a region key to impulse control. A significant age-by-BMI interaction was observed in both adolescents and adults; however, the direction of this relationship differed between age groups. In adolescents, increased age-adjusted BMI Z-score attenuated age-related thinning globally and in the right superior frontal gyrus. In adults, increased BMI augmented age-related CT reductions, both globally and in bilateral parietal cortex. Although DD was unrelated to adiposity in both groups, increased DD and BMI were both associated with reduced IFG thickness in adults. Our findings suggest that the known agerelated changes in CT in adolescence and adulthood are altered by adiposity. The impact of weight on cortical development and its functional implications would suggest that future studies of adolescent and adult brain development take adiposity into account.

Assessing a multivariate model of brain-mediated genetic influences on disordered eating in the ABCD cohort

“…Given that surface area peaks and cortical thickness begins to decline in early adolescence [20], our results may suggest that greater genetic risk for high BMI is associated with protracted brain maturation. This complements findings at the phenotypic level, linking increased BMI Z-score for age [77] and visceral fat mass [78] to greater cortical thickness, particularly of frontotemporal and occipital areas, in adolescence. Increased areal expansion and gyrification during development likely reflect a combination of cellular (e.g., synaptogenesis, gliogenesis, or intracortical myelination) and environmental (e.g., rearing environment) factors that facilitate increased functional integration of the cortex [79].…”

Inflammatory agents partially explain associations between cortical thickness, surface area, and body mass in adolescents and young adulthood

“…To date, studies in adolescents assessing the relationship between cortical thickness and body weight are scarce and have produced conflicting results. While two studies showed a negative link between obesity and cortical thickness [12,13], others found no relationship with obesity or BMI [14][15][16][17]. Notwithstanding, one of these works that did not identify any effect of BMI on healthy adolescents' cortical thickness observed a significant age-by-BMI z-score interaction related to altered cortical thickness across development [17].…”

“…Child and-youth obesity are rising at an alarming rate. According to the World Health Organization (WHO), over 340 million children and adolescents aged [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] were overweight or obese in 2016 [1]. This is a worldwide source of concern because excessive weight during youth has been associated with an increased incidence of cardiometabolic diseases (e.g., type II diabetes, stroke, and hypertension), some types of cancer, and premature mortality in adulthood [2].…”

“…While two studies showed a negative link between obesity and cortical thickness [12,13], others found no relationship with obesity or BMI [14][15][16][17]. Notwithstanding, one of these works that did not identify any effect of BMI on healthy adolescents' cortical thickness observed a significant age-by-BMI z-score interaction related to altered cortical thickness across development [17]. Likewise, it is also worth pointing the recent study of Ronan and colleagues [18], since they found that increased BMI was associated with reduced cortical thickness in several regions of the prefrontal cortex in a sample of 2700 healthy children aged between 9 and 11.…”

Body mass variations relate to fractionated functional brain hierarchies

“…In our analyses, this allowed for an integration of functional findings with morphological and microstructural measures in the same participants. Previous studies have explored morphological substrates of BMI variations, reporting cortical thinning in lateral prefrontal, entorhinal, and parahippocampal regions as BMI increases, indicating that overweight and obese people have reduced cortical thickness compared to people with a normal body weight (Medic et al, 2016;Ronan et al, 2019;Shaw et al, 2018;Vainik et al, 2018;Veit et al, 2014;Westwater et al, 2019). A recent multi-site study confirmed that high BMI (≥ 30) relates to reduced cortical thickness in temporal and frontal regions (Opel et al, 2020).…”