The relationship between body mass index and incidental mild cognitive impairment, Alzheimer's disease and vascular dementia in elderly.

OBJECTIVE: To examine the association between body mass index (BMI) and cognitive decline (CD) due to Mild Cognitive Impairment (MCI), Alzheimer's Disease (AD), and Vascular Dementia (VaD). DESIGN AND SETTING: The subjects aged ≥ 65 years were recruited prospectively from the Geriatrics Clinic of Gulhane Medical School, between 2004 and 2008 years. PARTICIPANTS: 1302 patients were included in the study. MEASUREMENTS: Cognitive status, clinical diagnosis of CD (MCI, AD, and VaD) and clinical and environmental risk factors were evaluated by comprehensive geriatric assesment. Finally, the subjects were categorized into two groups according to having CD or not. RESULTS: 905 (69.5%) subjects were not having CD whereas 397 (30.5%) patients with CD. Of the patients with CD, 140 (10.4%) had MCI, 227 (16.9%) AD, and 30 (2.2%) VaD. After adjustment for confounding with a model for multiple regression analysis, age (OR=1.054; CI:1.027-1.083; p < 0.001) and family history of dementia (OR=1.662; CI:1.038-2.660; p=0.034) were found to be independent risk factors for CD. Also, overweight (OR=0.594; CI:0.370-0.952; p=0.03) and obese (OR=0.396; CI:0.242-0.649; p < 0.001), and high education level (OR=0.640; CI:0.451-0.908; p=0.012) were found to be independent protective factors for CD. CONCLUSIONS: We found the risk of CD decreases in overweight and obese elderly. The results indicate that the primary prevention should not only consider risk factors, but must also take anthropometric data into consideration in order to identify persons at high risk for CD.