Cognitive Impairment in Sexual and Gender Minority Groups: A Scoping Review of the Literature.

Purpose: The purpose of this review was to synthesize evidence on differences in cognitive impairment by sexual orientation/gender identity (SOGI) status. Methods: A scoping review of the literature was conducted. Five databases (PubMed/Medline, Cumulated Index to Nursing and Allied Health Literature, Web of Science, PsycInfo, and Embase) were searched for primary articles comparing incidence or prevalence of cognitive impairment among sexual and gender minority (SGM) groups versus non-SGM groups. Two reviewers independently screened articles and conducted risk-of-bias assessment on eligible articles. Results: Fifteen primary studies were eligible. Most studies (n = 13) were cross-sectional, with moderate to critical risk of bias. Among eight studies examining self-reported cognitive impairment, seven reported a higher prevalence among some SGM groups versus non-SGM groups. Among seven studies using objective measures of cognitive impairment, three examined prevalence of clinician-documented diagnosis of dementia, of which two reported a higher prevalence specifically among transgender versus cisgender individuals. Among the other four studies examining objective measures, two reported poorer cognitive performance or memory, one reported better performance, and another reported no difference. Comparisons across studies were challenging due to inconsistencies in how SOGI and cognitive impairment were operationalized, and the factors used for statistical adjustment; some studies adjusted for putative intermediary factors that potentially explain differences in cognitive impairment. Conclusions: Whereas most published studies identified a positive relationship between SOGI status and self-reported cognitive impairment, evidence is mixed with regard to objective cognitive performance. Well-designed longitudinal, observational studies are needed, using objective measures of cognitive function, with careful consideration of confounding versus intermediary risk factors.