The effects of sex and gender attributes on functional outcomes: A systematic review

Background Biological sex and sociocultural gender may influence changes in health status critical to functional outcomes, yet scientific evidence of their effects on functional capacity remain uncertain. This research synthesized the scientific evidence on the impact of sex and gender attributes on functional outcomes. Methods Medline, Embase, PsycINFO, Web of Science and CINAHL were searched for studies using standardised measures to capture the association between sex and gender attributes and functional outcomes. Study quality was assessed using the National Institutes of Health assessment tools. Results were grouped by attribute and functional category. The certainty of evidence assessment considered consistency in the reported associations and study quality. Results Of the 12,948 records identified, ten studies (two of excellent, three of good, and five of fair quality) with a total of 10,506 participants (88.2% male) reported on the association between attributes of gender (e.g., gender identity, roles, and adherence to masculine norms) and physical, behavioral, and daily life functioning. None of the studies addressed sex attributes. The substantial heterogeneity in the consistency and significance of the findings across sex-specific and mixed-sex samples resulted in very low overall certainty in the evidence. Conclusion There is a gap in the evidence on the effect of sex attributes on functional outcomes and substantial heterogeneity in the reported associations between various gender attributes and functional outcomes. Further, the existing evidence concerns largely male participants. Research directed at separating the effects of sex from those of gender to determine their independent contributions to variability in outcomes across the sexes is timely.