Background: Primary ovarian insufficiency (POI) is an enigmatic condition that affects \~1/10,000 women by age 20. Sometimes referred to as "early menopause," POI is characterized by estrogen deficiency among other hormonal abnormalities that resemble the menopause. POI is a serious chronic condition with no cure. The clinical presentation or 'phenotype' in adolescents is not well understood. Health consequences may include delayed or arrested puberty, skeletal losses, and the threat to reproductive health. Both the metabolic and emotional sequelae are substantial, and one of the most concerning is compromised bone health. The optimal hormone replacement therapy (HRT) regimen for these young women is debated and practice varies among health providers. Importantly only sparse data exist to guide clinicians to make evidence-based decisions regarding the management of these patients. If initiated early, HRT may prevent estrogen-associated bone loss.

Impact: Better understanding of POI may lead to improved treatments for this underserved population and have significant implications for the treatment of estrogen deficiency in other populations of adolescents and young women, and for all women going though natural menopause later in life. Little is known about the effects of HRT on bone health, body composition, cognition, and health-related quality of life, especially among adolescents. Understanding how this therapy affects these multiple health outcomes will fill knowledge gaps regarding treatment for young patients with POI, with potential implications for adolescents and young women with estrogen deficiency in other clinical settings. We will define the clinical presentation (i.e., phenotype) of adolescent POI. The pilot data collected will be used in a future application to the National Institutes of Health, to fund a larger trial that builds on observations from this initial study. The information gained from this pediatric model may also provide insights on management of the natural menopause that occurs in all women later in life.

Methods: Ten adolescents with idiopathic POI (i.e., from unexplained causes) will be recruited through the Cincinnati Children's Hospital Medical Center (CCHMC) Teen Health Center, Endocrine or Pediatric/Adolescent Gynecology Clinics. Ten healthy controls will be recruited from the Teen Health Center. Participants with POI will receive transdermal estrogen replacement (beginning at 25 µg/patch applied weekly), with the dose increased at subsequent study visits that will occur at 3, 6, 12, 18, and 24 months. All data collection will take place at the CCHMC Schubert Research Clinic. The investigators will measure bone density of the central skeleton and body composition by dual-energy x-ray absorptiometry. To evaluate the peripheral skeleton, bone and muscle measures will be obtained by peripheral quantitative computed tomography. At each visit, the participants will have blood drawn to measure circulating hormone levels that are characteristically altered in adolescents with POI, along with safety assays. Cognitive functioning will be assessed using standardized tools. Participants will complete quality of life assessments, along with nutrition and physical activity surveys. Lastly, all participants will also complete a detailed medical history and health assessment.

Implications/Future Directions: Once the phenotype of adolescent POI is more clearly defined, a logical next question will be to determine whether negative health outcomes can be prevented or modified. Data from the proposed trial will guide the design of future prospective studies that evaluate the effects of traditional treatments (e.g., HRT), including a longer study to monitor HRT therapy, as well as more experimental treatments (e.g., skeletal agents) that may benefit young women with this rare condition. In addition, findings are expected to open avenues of research for adolescents and women with estrogen deficiency in other clinical settings.