The purpose of the ADCC is to identify and characterize early risk factors that predict cognitive decline and dementia in asymptomatic adults and adults with early signs of cognitive impairment. The data obtained from this study, collected at enrollment and follow-up will allow us to examine disease trajectory in individuals with and without prediabetes and other measures of glucoregulatory dysfunction in this process. The enrollees, who will be well-characterized with regard to cognitive and metabolic status through ADCC assessments, will provide an important resource for other local (institution) and national investigations. Data collected from participants enrolled in the ADCC will be stored indefinitely for future investigations.