The Adverse Childhood Experiences Study (ACE Study) is a research study conducted by the American health maintenance organization Kaiser Permanente and the Centers for Disease Control and Prevention. Participants were recruited to the study between 1995 and 1997 and have been in long-term follow up for health outcomes. The study has demonstrated an association of adverse childhood experiences (ACEs) with health and social problems as an adult. The study is frequently cited as a notable landmark in epidemiological research, and has produced more than 50 scientific articles and more than 100 conference and workshop presentations that look at the prevalence and consequences of ACEs.
In the 1980s, the dropout rate of participants at Kaiser Permanente's obesity clinic in San Diego, California, was about 50%; despite all of the dropouts successfully losing weight under the program. Vincent Felitti, head of Kaiser Permanente’s Department of Preventive Medicine in San Diego, conducted interviews with people who had left the program, and discovered that a majority of 286 people he interviewed had experienced childhood sexual abuse. The interview findings suggested to Felitti that weight gain might be a coping mechanism for depression, anxiety, and fear.
Felitti and Robert Anda from the Centers for Disease Control and Prevention (CDC) went on to survey childhood trauma experiences of over 17,000 Kaiser Permanente patient volunteers. The 17,337 participants were volunteers from approximately 26,000 consecutive Kaiser Permanente members. About half were female; 74.8% were white; the average age was 57; 75.2% had attended college; all had jobs and good health care, because they were members of the Kaiser health maintenance organization. Participants were asked about 10 types of childhood trauma that had been identified in earlier research literature: