Obesity is implicated in brain and cognitive health, but the long-term impact of obesity trajectories on brain and cognitive aging 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. These gaps are addressed by 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 aging. These findings indicate that persistent obesity could serve as a potential biomarker for assessing brain aging. Therefore, reducing both the severity and duration of obesity exposure may be crucial for preserving brain health.
