Risk of Incident Dementia According to Metabolic Health and Obesity Status in Late Life: A Population-Based Cohort Study

The risk for dementia among subjects who are obese with normal metabolic profiles, or called metabolically healthy obese (MHO), remains uninvestigated. Objective: To determine the association between late-life metabolic health and obesity status and risk of incident dementia. Design: Retrospective cohort study. Setting: The National Health Insurance System, Republic of Korea. Patients: A total of 12,296,863 adults.50 years old who underwent health examinations from 2009 to 2012 without baseline history of dementia. Main Outcome Measure: Incident overall dementia, Alzheimer's disease (AD), and vascular dementia (VaD). Results: Among subjects 60 years old, 363,932 (6.4%) developed dementia during a median followup of 65 months (interquartile range 51 to 74months). TheMHO group showed the lowest incidence of overall dementia [hazard ratio (HR) 0.85; 95%CI, 0.84 to 0.86] andAD(HR0.87; 95%CI, 0.86 to 0.88), but not VaD, comparedwith themetabolically healthy nonobese group. All components ofmetabolic syndrome except obesity significantly elevated the risk of dementia, and these associationsweremore pronounced in VaD. In particular, being underweight dramatically increased the risk of dementia.