PolyU research reveals sustained obesity may accelerate brain ageing

With the global prevalence of obesity on the rise, it is crucial to explore the neural mechanisms linked to obesity and its influence on brain and cognitive health. However, the impact of obesity on the brain is complex and multilevel. To address this, Prof. Anqi QIU, Professor of the Department of Health Technology and Informatics at The Hong Kong Polytechnic University (PolyU) and Global STEM Scholar, has unveiled novel research to advance our understanding of the neural mechanisms underlying the relationship between obesity and its implications for cognitive health in adults.

Obesity is implicated in brain and cognitive health, but the long-term impact of obesity trajectories on brain and cognitive ageing remains insufficiently understood. Most existing research primarily relies on cross-sectional samples, making it difficult to distinguish between chronic and temporary obesity. It is also unclear whether varying levels of obesity over time affect brain anatomy and function differently. Importantly, Prof. Qiu’s research addresses these gaps by conducting a comprehensive longitudinal analysis of obesity trajectories and their impacts on brain and cognitive health in adults.

Drawing on multifaceted obesity measurements from the UK Biobank, the study identifies five distinct obesity trajectories: low-stable, moderate-stable, high-stable, increasing and decreasing. Significantly, the study examines how these obesity patterns influence brain morphology, function and cognition in middle-aged and older adults, offering deeper insights into their long-term neurological effects.

Notably, individuals in the decreasing trajectory showed minimal adverse effects on brain structure and cognitive performance compared to those in the low-stable group. In contrast, the increasing, moderate-stable, and high-stable trajectories were associated with progressively greater impairment in brain structure, functional connectivity, and cognitive abilities. Specifically, these adverse effects began in the fronto-mesolimbic regions for the increasing trajectory, extended to parietal and temporal regions in the moderate-stable group, and ultimately led to widespread brain abnormalities in the high-stable group.

The research highlights the dynamic relationship between obesity progression and brain-cognitive health, underscoring the clinical importance of long-term monitoring and management of obesity through a multifaceted approach. It reveals a distinct, progressive pattern of brain deterioration linked to obesity, suggesting that sustained obesity may accelerate brain ageing. These findings indicate that persistent obesity could serve as a potential biomarker for assessing brain ageing. Therefore, reducing both the severity and duration of obesity exposure may be crucial for preserving brain health.

Prof. Qiu said, “As the ageing population grows, there has been a notable rise in neurodegenerative diseases, such as Alzheimer’s disease, Parkinson’s disease, and others, that currently lack a cure. This research proposes that maintaining long-term weight control can contribute to improved brain health.” Looking ahead, the research team plans to integrate multi-omics approaches to explore the biological pathways that influence both brain and body health.

The research, “Long-term obesity impacts brain morphology, functional connectivity and cognition in adults” has been published in Nature Mental Health. The study extracted obesity measure, brain images and cognition from the UK Biobank database, which comprised over 500,000 participants aged 40 years and above with diverse ethnic backgrounds.

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