Hidden fat spots may speed up brain aging, study shows

A large UK Biobank analysis of over 18,000 middle-aged and older adults finds that fat distribution—arm, leg, trunk, and especially visceral fat around internal organs—independently shapes brain structure, connectivity, and cognitive performance beyond BMI. Arm and trunk fat are linked to sensorimotor cortex thinning and hippocampal volume loss; leg fat affects limbic networks; visceral fat shows the strongest association with white-matter deterioration and faster brain aging as estimated by a Brain Age model. These patterns persist after adjusting for BMI, but the cross-sectional design means causality cannot be established.