Obesity accelerates brain ageing: a multimodal imaging study

Obesity is a global health concern, and it is thought to accelerate the normal ageing process. Obesity has also been linked to neurodegenerative processes, possibly as a manifestation of accelerated brain-ageing. In this cross-sectional study we combined multimodal neuroimaging data and machine learning techniques to assess the discrepancy between brain-based predicted age and chronological age, known as brain age delta, in obese participants and in normal-weighted individuals using a tight matching for age, gender and education across groups. Data were taken from the publicly available dataset ‘The Cambridge Centre for Ageing and Neuroscience (Cam-CAN)’ covering the adult lifespan (18–90 years old). Overall, brain age delta was greater in obese individuals for grey matter (GM) and functional connectivity (intra- and inter-network connectivity) measures. When considering the age-range, the difference between groups peaked in mid-age (40–60 years old) for GM, while for intra-network connectivity it was more marked in late age (60–90 years old). Overall, our results provide evidence to the hypothesis that obesity accelerates the brain ageing process, with the earliest effect already evident in the 40–60 age range. Earlier intervention on obesity might contribute to maintain a healthy brain potentially reducing the risk of developing late-life brain-related pathologies.