Cognitive functioning can be negatively influenced by age, cardiovascular risk (CVR) and mental health challenges, and sex-hormones can have neuroprotective effects. Little is known about cognitive functioning in older transgender individuals receiving long-term gender-affirming hormone therapy (GHT). In a previous study, cognitive differences between transgender women and cisgender groups were minimal, yet statistically significant. The current study assessed cognitive differences between larger samples of older transgender and cisgender individuals and the contribution of CVR and mental/social health to these differences.
This cross-sectional study compared 73 transgender women and 39 transgender men (>54y) receiving long-term GHT (>10y) with matched (age/education level) cisgender women and men from Longitudinal Aging Study Amsterdam on cognitive functioning assessed with neuropsychological tests. Mean z-scores per cognitive domain were analysed using linear regression. Models were then adjusted for CVR and mental/social health factors.
Transgender women had lower scores than cisgender women and men, respectively, on information-processing speed (b=-0.62, 95%CI -0.90 to -0.35; b=-0.33, 95%CI -0.60 to -0.05), episodic memory (b=-1.28, 95%CI -1.53 to -1.04; b=-0.77, 95%CI -1.01 to -0.52) and crystallized intelligence (b=-0.42, 95%CI -0.75 to -0.10; b=-0.41, 95%CI -0.75 to -0.08). Transgender men scored lower on episodic memory than cisgender women but equal to cisgender men (b=-0.43, 95%CI -0.79 to -0.08; b=-0.01, 95%CI -0.36 to 0.35). Mental/social health largely, and CVR slightly, explained cognitive differences between trans- and cisgender groups.
Small cognitive differences between transgender men and cisgender groups do not suggest adverse or beneficial long-term testosterone effects on cognitive functioning. However, transgender women had lower cognitive functioning than cisgender groups as was largely explained by mental/social health. This warrants further research and clinical awareness of mental and cognitive health in older transgender individuals.