Considerations for transgender population health research based on US national surveys.

Transgender identities and health are highly politicized in the United States leading to restrictions on relevant data collection in national health surveillance systems. This has serious implications on transgender population health research; an urgent area of study given the systemic discrimination faced by transgender individuals and the resultant social and health inequities. In this precarious political climate, obtaining high-quality data for research is challenging and in recent years, two data sources have formed the foundation of transgender health research in the United States, namely the 2015 United States Transgender Study and the Behavioral Risk Factor Surveillance System after the launch of the optional Sexual Orientation and Gender Identity Module in 2014. While useful, there are serious challenges to using these data to study transgender health, specifically related to survey weighting methodologies, ascertainment of gender identity, and study design. In this article, we detail these challenges and discuss the strengths and weaknesses of various methodological approaches that have been implemented as well as clarify several common errors that exist in the literature. We feel that this contribution is necessary to provide accurate interpretation of the evidence that currently informs policy and priority setting for transgender population health and will provide vital insights for future studies with these now ubiquitous sources of data in the field.