Obesity impacts brain metabolism and structure independently of amyloid and tau pathology in healthy elderly

• Main Authors: Jordi Pegueroles, Adriana Pané, Eduard Vilaplana, Víctor Montal, Alexandre Bejanin, Laura Videla, María Carmona‐Iragui, Isabel Barroeta, Ainitze Ibarzabal, Anna Casajoana, Daniel Alcolea, Silvia Valldeneu, Miren Altuna, Ana deHollanda, Josep Vidal, Emilio Ortega, Ricardo Osorio, Antonio Convit, Rafael Blesa, Alberto Lleó, Juan Fortea, Amanda Jiménez, Alzheimer's Disease Neuroimaging Initiative
• Format: Article
• Language: English
• Published: Wiley 2020-01-01
• Series: Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring
• Subjects: body mass index; cerebrospinal fluid Alzheimer's disease biomarkers; fluorodeoxyglucose PET; magnetic resonance imaging; obesity; pre‐clinical Alzheimer's disease
• Online Access: https://doi.org/10.1002/dad2.12052
• ISSN: 2352-8729

Abstract Aims/hypothesis Midlife obesity is a risk factor for dementia. We investigated the impact of obesity on brain structure, metabolism, and cerebrospinal fluid (CSF) core Alzheimer's disease (AD) biomarkers in healthy elderly. Methods We selected controls from ADNI2 with CSF AD biomarkers and/or fluorodeoxyglucose positron emission tomography (FDG‐PET) and 3T‐MRI. We measured cortical thickness, FDG uptake, and CSF amyloid beta (Aβ)1‐42, p‐tau, and t‐tau levels. We performed regression analyses between these biomarkers and body mass index (BMI). Results We included 201 individuals (mean age 73.5 years, mean BMI 27.4 kg/m2). Higher BMI was related to less cortical thickness and higher metabolism in brain areas typically not involved in AD (family‐wise error [FWE] <0.05), but not to AD CSF biomarkers. It is notable that the impact of obesity on brain metabolism and structure was also found in amyloid negative individuals. Conclusions/interpretation In the cognitively unimpaired elderly, obesity has differential effects on brain metabolism and structure independent of an underlying AD pathophysiology.