The investigators propose to investigate the definition of hormone overdose and misuse (HODM) in Chinese transgender and gender nonconforming population (TGNCs), address the incidence of HODM in Chinese TGNC population, related factors and risks, identify the probable causes of HODM, and follow up HODM individuals to explore long-term effects.

The research questions are:

Q1 What is the definition and the criteria of HODM in Chinese TGNC population? Q2 What is the prevalence of HODM in Chinese TGNC population? Q3 What factors and risks are relevant to HODM? Q4 What are the causes? Q5 What are the long-term effects of HODM in Chinese TGNC population, compared to those who enroll in regular GAHT regimens?

The investigators decide to employ a mixed-methods design to construct a full research framework on HODM. A prospective cohort study is a component of the study.

The study can be divided into four stages to address research questions. Stage I will establish a precise definition and eligibility criteria of HODM through expert panel meeting and stakeholder engagement. Subsequently, a cross-sectional study will be conducted to evaluate the rate, subtypes, and related factors of HODM in Chinese TGNCs. In Stage III, semi-structured interviews and focus groups for TGNCs who are identified as HODM will be employed to investigate the causes, motivations and personal impact factors. This stage will be divided into two phases, Stage III-a before the cross-sectional study to provide a brief picture of HODM behaviors, and Stage III-b after the cross-sectional study to draw an overall pattern. Lastly, all participants of Stage II or III who would like to participate in our follow-up will be included in prospective cohorts to assess long-term effects.

Among the stages, the cohort study is the subject of the registration. The investigators propose two cohorts in the study. Participants who are identified as HODM will be assigned to cohort 1 [HODM cohort], and those who are identified as regular GAHT use will be assigned to cohort 2 [non-HODM cohort]. Participants will be asked to report their gender-related and hormone use-related conditions, and mental health-related conditions at specific timepoints. The investigators will compare the HODM cohort to the non-HODM cohort to see if the overall incidence of adverse effects, gender-related, hormone-related, and mental health-related conditions differ in the cohorts.