by Asa Farahani, Zhen-Qi Liu, Filip Morys, Roqaie Moqadam, Yashar Zeighami, Mahsa Dadar, Alain Dagher, Bratislav Misic The brain and body undergo coordinated changes throughout the life span, yet studies of aging have traditionally examined these systems as separate entities. Here we ask how brain health relates to aging and peripheral biomarkers of metabolic and vascular function, including body mass index, blood pressure, and blood biochemistry. We use multivariate pattern learning to identify generalizable patterns of covariance between multi-modal neuroimaging data (structural, functional, diffusion, and arterial spin labeling MRI), demographic, and physiological markers in two large-scale deeply phenotyped datasets: the Human Connectome Project–Aging and UK Biobank. This data-driven approach isolates two principal axes of brain–body associations in both biological sexes. The first axis is driven by the dominant contribution of age. Across multiple brain measures, aging is associat