The aim of this prospective longitudinal study is to investigate the risks associated with use of anabolic steroids in fitness circles in Denmark in order to assess the scope of therapeutic need existing as a consequence of use. The objectives are: * To assess long-term complications and outcomes related to: cardiovascular disease, diabetes, gonadal disease (women and men) and psychiatric disease using data from Danish registries including addressing central questions such as whether the following characteristics play a role for development of overt disease * Characterization of illicit AAS use among men and women * Current male reproductive health * Current psychological well-being, aggressive tendencies, cognitive function and quality of life * Current cardiovascular and metabolic status The participants will undergo: * Semi-structured medical interview * Physical examinations * Questionnaires * Blood and urine sampling * Dual X-ray Absorptiometry With a subset undergoing further testing, including semen analysis, gonadotropin-releasing hormone (GnRH) and human chorionic gonadotropinm (hCG) stimulation and 82Rubidium positron emission tomography and computer tomography (PET/CT). Register-based follow-up is planned every third year until the 15th year, marking the completion of the trial. The study will include 800 participants with current or former AAS use and 100 participants (80 male; 20 female) as controls with no former or current use of AAS.