Preliminary evidence of cognitive and brain abnormalities in uncomplicated adolescent obesity

Abstract

Objective We ascertain whether pediatric obesity without clinically-significant insulin resistance (IR) impacts brain structure and function. Design and Methods Thirty obese and 30 matched lean adolescents, all without clinically-significant IR or a diagnosis of metabolic syndrome (MetS), received comprehensive endocrine, neuropsychological, and MRI evaluations. Results Relative to lean adolescents, obese non-IR adolescents had significantly lower academic achievement (i.e. arithmetic and spelling) and tended to score lower on working memory, attention, psychomotor efficiency and mental flexibility. In line with our prior work on adolescent MetS, memory was unaffected in uncomplicated obesity. We also uncovered reductions in the thickness of the orbitofrontal and anterior cingulate cortices as well as reductions of microstructural integrity in major white matter tracts without gross volume changes. Conclusions We document, for the first time, that adolescents with uncomplicated obesity already have subtle brain alterations and lower performance in selective cognitive domains. When interpreting these preliminary data in the context of our prior reports of similar, but more extensive brain findings in obese adolescents with MetS and T2DM, we conclude that “uncomplicated” obesity may also result in subtle brain alterations, suggesting a possible dose effect with more severe metabolic dysregulation giving rise to greater abnormalities.

Effects of aging on slow-wave sleep dynamics and human spatial navigational memory consolidation

“…Gray matter cortical volumes were calculated using Freesurfer image analysis software, version 5.1 (http://surfer.nmr.mgh.harvard.edu/) from MPRAGE sequences (Yau et al, 2014). Motion correction, skull stripping, Talairach transforms, atlas registration, spherical surface maps and parcellations were performed automatically using a within-subject template (Reuter et al, 2012).…”

Greater body mass index is associated with reduced frontal cortical volumes among adolescents with bipolar disorder

“…17 In youth, BMI is most consistently associated with reduced grey matter volume in the frontal lobe (FL), specifically in the prefrontal cortex (PFC) and orbitofrontal cortex (OFC). [17][18][19][20][21][22] There is also evidence of reduced volume of medial temporal lobe (MTL) structures, such as the hippocampus and parahippocampal gyrus in overweight and obese adolescents. 23 The FL regions are of particular relevance to BD because they are associated with higher-level cognitive processes, such as executive functioning, decisionmaking and inhibitory control, and are also known to modulate emotion processing.…”

Obesity, fitness, and brain integrity in adolescence

“…Given that aerobic exercise can attenuate volume loss over time, it may be an effective strategy for reversing the significant brain volume deficits in obese individuals (10,16). While gross brain volume reductions have been observed in individuals with type 2 diabetes mellitus (T2DM) and metabolic syndrome, more sensitive measures, such as cortical thickness, may be necessary to detect the impact of more subtle forms of metabolic disease on the brain in adolescents (18). …”

“…We recently described brain abnormalities in adolescents with uncomplicated obesity and found reduced brain structural integrity in the OFC and ACC cortices (18). Insulin sensitivity and fitness are linked, thus, we wanted to contrast how a simple measure of fitness would explain brain structure and function relative to measures of insulin sensitivity and abdominal obesity, which are associated to brain integrity.…”