Association of body-mass index with physiological brain pulsations across adulthood – a fast fMRI study

• Published in: International Journal of Obesity Vol. 48; no. 7; pp. 1011 - 1018
• Main Authors: Raitamaa, Lauri, Kautto, Joona, Tuunanen, Johanna, Helakari, Heta, Huotari, Niko, Järvelä, Matti, Korhonen, Vesa, Kiviniemi, Vesa
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.07.2024; Nature Publishing Group
• Subjects: 59/36; 59/57; 631/378/1488/393; 692/308/575; Adult; Amplitudes; Body Mass Index; Brain; Brain - diagnostic imaging; Brain - physiology; Brain mapping; Cardiovascular diseases; Cerebrospinal fluid; Cerebrovascular Circulation - physiology; Cognitive ability; Dementia disorders; EEG; Efflux; Epidemiology; Female; Fluid flow; Functional magnetic resonance imaging; Health Promotion and Disease Prevention; Homeostasis; Humans; Internal Medicine; Magnetic resonance imaging; Magnetic Resonance Imaging - methods; Male; Medicine; Medicine & Public Health; Metabolic Diseases; Metabolites; Middle Aged; Neuroimaging; Obesity; Obesity - metabolism; Obesity - physiopathology; Physiological effects; Physiology; Population studies; Public Health; Pulsation; Regression models; Risk factors; Temporal resolution; Very Low Frequencies; Young Adult
• ISSN: 0307-0565; 1476-5497; 1476-5497
• DOI: 10.1038/s41366-024-01515-5

Background/objective Obesity is a risk factor for several brain-related health issues, and high body-mass index (BMI) is associated with an increased risk for several neurological conditions, including cognitive decline and dementia. Cardiovascular, respiratory, and vasomotor brain pulsations have each been shown to drive intracranial cerebrovascular fluid (CSF) flow, which is linked to the brain metabolite efflux that sustains homeostasis. While these three physiological pulsations are demonstrably altered in numerous brain diseases, there is no previous investigation of the association between physiological brain pulsations and BMI. Subjects/methods We measured the amplitudes of the physiological brain pulsations using amplitude of low frequency fluctation (ALFF) based method with resting-state functional magnetic resonance imaging via high temporal resolution whole-brain magnetic resonance encephalography (MREG) in 115 healthy subjects. We next undertook multiple linear regression to model the BMI effect voxel-wise whole-brain on very low frequency (VLF), respiration, cardiovascular, and respiratory induced modulation of cardiovascular pulsation amplitudes with age, pulse pressure, and gender as nuisance variables. Results In our study population, BMI was positively associated with the amplitudes of vasomotor, respiratory, and respiratory induced modulations of cardiovascular pulsations ( p  < 0.05), while negatively associated with the amplitudes of cardiovascular pulsations ( p  < 0.05). Conclusions The findings suggest that BMI is a significant factor in alterations of cardiovascular pulsation of neurofluids. As physiological pulsations are the drivers of CSF flow and subsequent metabolite clearance, these results emphasize the need for further research into the mechanisms through which obesity affects brain clearance.