The Fels Longitudinal Study was founded in Yellow Springs, Ohio, in 1929 as part of the Fels Research Institute. At that time, the Fels Longitudinal Study was one of five similar studies that began in the United States between 1927 and 1932. The Fels Study was originally designed to study child growth and development. Physical growth, maturation and the psychological development of children were early key research areas of interest in the Fels Longitudinal Study. Later, the Fels Longitudinal Study focused on physical growth, skeletal maturation, body composition, risk factors for cardiovascular disease and obesity, skeletal and dental biology, longitudinal biostatistical analyses and aging. In 1977, the Fels Research Institute and the Fels Longitudinal Study became part of the Wright State University’s Boonshoft School of Medicine, residing first in the Department of Pediatrics and later within the Department of Community Health in its Lifespan Health Research Center. The Fels Longitudinal Study was the longest operational longitudinal study of its kind in the world.
The original location of the Fels Longitudinal Study was Yellow Springs, Ohio, because in 1929, Arthur Morgan, then president of Antioch College in Yellow Springs, posed the question, "What makes people different?". He approached Samuel Fels, a Philadelphia businessman and philanthropist, regarding not only this question, but his idea that a longitudinal study from birth to adulthood would be required to answer to this question. Mr. Fels gave Morgan the backing needed to begin the study, and Lester W. Sontag M.D., Antioch College’s physician, was appointed the first director of the Fels Longitudinal Study in 1929. The first participants were enrolled prenatally by their parents, and the first examinations began in 1930. Dr. Sontag remained active in the study, developing, nurturing and guiding it until his retirement in 1970.
The Fels Research Institute was owned and operated by the Fels Fund of Philadelphia, a fund set up by Samuel Fels to continue his philanthropic endeavors. By the 1950s, the Fels Institute was also receiving additional support from the U.S. government from grants and contracts through the National Institutes of Health. In 1977, the Fels Fund donated the Institute to Wright State University School of Medicine, and the Institute was absorbed into the School of Medicine.
The original design of the Fels study called for the Fels participants to be enrolled into the study during the pregnancy of the mother, with the first measurements taken at or near the time of birth. Between 10 and 20 participants were enrolled each year. Some of the first mothers also became pregnant again, and their subsequent children, the siblings to the first participants, were also enrolled into the study. Over the years, as these first participants reached adulthood and started to have their own children, many of these second generation children were also enrolled. Eventually most of their children, grandchildren and great-grandchildren became dedicated Fels participants.
The dedication of Fels Longitudinal Study participants generated a wealth of significant health knowledge that has benefitted the people of the United States and of the world. One of the very first scientific papers on the effects of smoking on the fetus was published in 1936 using Fels data. The United States pediatric growth charts from 1978 to 2000 for children from birth to 3 years of age were produced exclusively from Fels data. The only valid method of measuring skeletal maturation (biological age) of U.S. children was developed using Fels data.