Reporting of tobacco use and health outcomes among transgender and gender expansive people in gender-affirming hormone therapy research: 1980-2024.

Purpose: Transgender/gender expansive (TGE) people, who use tobacco at high rates, are frequently advised not to use tobacco during gender-affirming hormone therapy (GAHT) due to increased risk of negative health events. However, there is no summary of studies reporting risk of negative health events for TGE people with versus without tobacco use during GAHT. This systematic review assesses what is known about tobacco use and health outcomes in studies of TGE people pursuing GAHT.

Methods: Searches were conducted in PubMed, Embase, PsycInfo, Google Scholar, and Mednar. The protocol was registered in Prospero (CRD42023416390).

Results: 107 studies published from 1980-2024 mentioned tobacco and GAHT for TGE patients. Most studies focused on adults (80.4%). Patient samples were feminine/transfeminine (29.9%), masculine/transmasculine (26.2%) or "both"/combinations (43.0%). Most studies (96.3%) reported smoking prevalence, ranging from 4.2% to 73.0%. Forty-three studies (40.2%) explored patient outcomes as they related to GAHT and tobacco use, but significantly increased risk of adverse health events for TGE people receiving GAHT with tobacco use relative to no tobacco use were found in only five studies (4.7%). Tobacco cessation was not mentioned in 79.4% of studies, and no studies reported offering cessation assistance.

Conclusion: Identifying whether TGE people pursuing GAHT experience unique or exacerbated outcomes based on whether and what type of tobacco they use is critical for TGE-focused clinicians and researchers. This systematic review found few studies that identified empirical associations between tobacco use and GAHT-related health outcomes. Accurate tobacco assessment is essential to discern associations with GAHT-related outcomes.