Associations Of Obesity With Brain, Cognitive Function, And Inflammatory Biomarkers In Women With Breast Cancer

PURPOSE: Breast cancer and obesity negatively affect brain health, but we know little about whether obesity in the context of breast cancer is related to brain health outcomes. Here, we assessed associations of BMI and body weight with brain volume, cortical thickness, inflammatory biomarkers, and objective cognitive function in postmenopausal women recently diagnosed with Stage I-IIIa breast cancer. METHODS: Twenty-three women (mean age = 62.92 ± 5.84 years) underwent magnetic resonance imaging (MRI), weight and height assessments for calculation of body mass index (BMI), neuropsychological testing, and blood extractions. FreeSurfer was used for calculation of regional volumes and cortical thickness from the MRI anatomical scan. Linear regressions were conducted to analyse the associations of BMI and weight with brain variables, cognitive performance, and inflammatory biomarkers. RESULTS: Higher BMI was associated with reduced cortical thickness of the paracentral gyrus (β = -0.492, p = .015) and posterior cingulate cortex (β = -0.407, p = .048). Similarly, greater weight was associated with reduced cortical thickness of the cuneus, entorhinal cortex, paracentral gyrus, and posterior cingulate cortex (all p < .05). These associations persisted after controlling for age and estimated total intracranial volume (eTIV). In contrast, higher BMI was associated with better performance on the two measures of processing speed (β = 0.546, p = .006; β = 0.542, p = .006) and greater weight was associated with better learning and memory, verbal memory, and processing speed (all p < .05). These associations persisted after adjusting for age and education. As hypothesized, higher BMI and weight was associated with greater levels of inflammation as measured by IL-6 (all p < .05) and TNF-alpha (β = 0.629, p < .001, and β = 0.419, p = .042, respectively). The associations were still observed after adjusting for age. CONCLUSIONS: Our results might be in line with the “obesity paradox” such that late-life obesity is associated with better cognitive performance. The associations with inflammatory markers indicate a possible mechanism for the cortical findings but more research is needed to understand the links with cognition.Supported by the National Cancer Institute [R01CA196762].