HANDLS participants are a fixed cohort of 3,720 community-dwelling African American and white adults aged 30-64. Participants were recruited from 13 pre-determined neighborhoods (groups of contiguous census tracts) comprising an area probability sample of Baltimore City. The area probability sample was designed to sample a wide range of socioeconomic and income circumstances in a 4-way factorial cross of age (seven five-year age bands between 30-64), sex, race, and socioeconomic status indexed by poverty status (below or above 125% of the Federal Poverty Guidelines for 2004). HANDLS is planned as a 20-year longitudinal study. Using our mobile research vehicles, we plan to re-visit each neighborhood for three months every three to four years.