Dementia and Diabetes Prevention Program

This is a multicenter, randomized 2-arm clinical trial of two lifestyle interventions varying in intensity and format, in 400 older African American and non-Hispanic whites at increased risk of cognitive decline and dementia in the East San Francisco Bay Area. The trial will include two lifestyle interventions that differ in intensity and format: 1. Aerobic Exercise (AEx) Intervention that involves aerobic activities with in-class walking workouts and tutorials and carried out at the East Oakland Sports Center (EOSC) and Tice Creek Fitness Center (TICE). 2. Dietary counseling to support adherence to the Mediterranean-Diet Approaches to Stop Hypertension (DASH) Intervention for Neurodegenerative Delay (MIND) diet to encourage increased consumption of berries, green leafy and other vegetables, whole grains, nuts, fish, poultry, beans and olive oil, and to reduce consumption of fried/fast foods, red meat, whole fat cheese, sweets, butter and trans-fat margarines.

Inclusion Criteria: * Sedentary (as per the Telephone Assessment of Physical Activity) * Poor diet (as per the MIND Diet Screener) * Cognitive function: absence of significant cognitive impairment as per the modified Telephone Interview for Cognitive Status (TICSm; age-, education-, and race-adjusted TICSm \>32) * Lives in a region where the DDPP interventions will be delivered * Does not plan to travel outside of the home geographic area for more than 3 months over the course of the study * Free of physical disabilities that preclude participation in the study * Willing to complete all study-related activities for 32 weeks * Willing to be randomized to either lifestyle intervention group Exclusion Criteria: * Age \40 * Any significant neurologic disease, including any form of dementia, Parkinson's disease, Huntington's disease, normal pressure hydrocephalus, brain tumor, progressive supranuclear palsy, seizure disorder, subdural hematoma, multiple sclerosis, or history of significant head trauma with persistent neurologic sequelae or known structural brain abnormalities * History of major depression within the last 12 months * History of bipolar disorder or schizophrenia as per Diagnostic and Statistical Manual of Mental Disorders (DSM) V criteria * History of alcohol or substance abuse or dependence within the past 2 years, as per DSM V criteria * Use of psychoactive medications within the last 3 months including tricyclic antidepressants, antipsychotics, mood-stabilizing psychotropic agents (e.g., lithium salts), psychostimulants, opiate analgesics, antiparkinsonian medications, anticonvulsant medications (except gabapentin and pregabalin for non-seizure indications), systemic corticosteroids, or medications with significant central anticholinergic activity; in the absence of major depression, stable dose use of selective serotonin reuptake inhibitors or serotonin and norepinephrine reuptake inhibitors are allowed * Health profiles that would jeopardize their safety to participate: (Screen failures will be referred immediately to a physician for medical examination): (1) Myocardial infarction or symptoms of unstable coronary artery disease (e.g., angina) in the last six months, (2) Uncontrolled hypertension within the past 6 months, (3) Morbid obesity (BMI\