Abstract

Dementia imposes significant personal and social burdens as the aging population increases. Dementia progression has a large impact on the lives of individuals, their families, and people around them. As treatment options for dementia are limited, strategies to prevent or delay its onset are important. Obesity is linked to cognitive decline and dementia, including Alzheimer’s disease, and can induce brain atrophy, vascular damage, chronic inflammation, or alter metabolic functions (e.g., insulin resistance). Previous studies have shown that mid-life obesity is detrimental to cognitive function and increases the risk of dementia. However, the impact of late-life obesity on the risk of dementia is controversial. The findings suggested that the impact of obesity on cognitive function varies across age groups, and factors other than body mass index should be considered when assessing obesity in old age. Based on recent studies, being underweight, unintentional weight loss, weight variability and sarcopenia are associated with an increased risk of dementia in old age, whereas being overweight and obese in old age reduces the risk of dementia. Prevention strategies such as physical activity, weight management, and dietary interventions in mid-life can improve cognitive functions and reduce dementia risk in late life. Diabetes medications, particularly glucagon-like peptide-1 receptor agonists, can reduce dementia risk. Overall, the findings demonstrated the importance of early intervention and consistent weight management across a lifespan for cognitive health.