Association between metabolically healthy obesity and risk of dementia: A systematic review and meta-analysis

Abstract

Background: Some studies suggest that the metabolic alterations linked to obesity in humans may increase the likelihood of developing dementia. However, there are currently no existing meta-analyses exploring the possible occurrence of dementia in patients with metabolically healthy obesity (MHO). In the present study, we aimed to investigate a potential correlation between individuals with MHO and the likelihood of developing dementia. Method: Our research focused on searching three databases to locate pertinent studies starting from January 10, 2023. We used sensitivity analysis, the Egger's test, and a visual funnel plot to separately assess the reliability of the research results and publication bias. We conducted this study according to a pre-established protocol in the PROSPERO registry (CRD42023449459). Results: We incorporated three potential cohort investigations. Individuals with good metabolic health and obesity showed a decreased likelihood of developing dementia compared with those who were metabolically healthy but not obese (hazard ratio (HR) = 0.79; 95% confidence interval (CI) 0.68–0.92). In contrast, individuals who were metabolically unhealthy and nonobese had an increased likelihood of developing dementia (HR = 1.33; 95% CI 1.25–1.42), whereas the population with metabolically unhealthy obesity did not exhibit a notable association with dementia onset (HR = 1.06; 95% CI 0.83–1.37). Conclusion: According to our meta-analysis, patients with MHO had a reduced likelihood of developing general dementia and Alzheimer disease. Maintaining a well-functioning metabolism can provide advantages in reducing the occurrence of dementia.