Neurocognitive deficits in a Class II and Class-III obesity cohort: contributions of type-2 diabetes and other comorbidities

OBJECTIVE: This study examined the relationship between specific metabolic and vascular risk factors and cognition in adults with severe obesity. METHODS: 129 adults (with BMI ≥ 35 kg/m(2)) underwent a baseline clinical evaluation and neuropsychological assessment. Regression analyses examined the relationship between cognition and medical factors (BMI, hemoglobin HbA1c, diabetes, hypertension, CPAP use, obstructive sleep apnea [OSA], and osteoarthritis). RESULTS: Diabetes was associated with deficits in overall cognitive performance, and in the executive, processing speed and verbal fluency domains. HbA1c was inversely related to overall cognitive performance and deficits in the attention domain. Participants using CPAP to treat OSA had stronger learning and memory performance, whereas OSA was associated with reduced total learning. Elevated BMI together with diabetes diagnosis were associated with reduced verbal fluency and greater variability in sustained attention. CONCLUSIONS: Obesity-associated comorbidities, most notably appear to have a greater relative influence on cognitive performance than BMI itself in adults with severe obesity. This likely reflects the fact the very elevated BMI was ubiquitous, and thereby probably exerted a similar influence among all adults in the cohort. Accordingly, in the context of severe obesity, diabetes and other comorbidities may have greater sensitivity to cognitive deficits than BMI alone. CLINICALTRIALS.GOV REGISTRY: Name: Obesity and Type 2 Diabetes, Bariatric Surgery Effects on Brain Function URL: https://clinicaltrials.gov/ct2/show/NCT02137070 NCT Identifier: Other Study ID Numbers: 201400034-N 1R01DK099334–01A1 (U.S. NIH Grant/Contract)