As of April 2024, the BLSA is America's longest-running scientific study of human aging. It began in 1958 in Baltimore, Maryland, United States, with 260 male participants ranging in age from late teens to almost 100 years old. In 1978, the study extended to include females. In 2024, more than 1,300 male and female participants ranging in age from their twenties to 100s attend regular data collection visits. Participants under age 60 are assessed every 4 years; those aged 60 to 79 years come every 2 years, and participants aged 80 and older are assessed annually. Since its inception, over 3,200 participants have contributed to the research.

Recruitment is ongoing