Functional social support subtypes as mediators of the association between depression and executive function: A moderated mediation analysis of the Canadian Longitudinal Study on Aging Comprehensive cohort

• Social support mediated the association between depression and executive function. • Mediation was moderated by age and sex, with variation by social support subtype. • Social support showed more pronounced and consistent mediation in women aged 75+. • Social support interventions may mitigate the impacts of depression on cognition. • These interventions may be most impactful in supporting cognition in older women. For adults living with depression, social support interventions may offer a potential strategy to protect key cognitive domains, such as executive function. However, the extent to which the association between depression and executive function is mediated by social support, and how this varies by specific subtypes of support, is unknown. The objective of this study was to investigate whether functional social support subtypes mediated the association between depressive symptoms and executive function, and whether this mediation was moderated by age and sex. Using the Canadian Longitudinal Study on Aging Comprehensive cohort (n=14,133) of community-dwelling adults 45 to 85 years at baseline and conditional process analysis of baseline and 3-year follow-up data, this study investigated whether functional (perceived) social support subtypes mediated the association between depressive symptoms and executive function, and whether this mediation was moderated by age and sex. Functional social support significantly mediated the association between depression and executive function, with this mediation varying by subtype of support, age, and sex. Overall, low levels of emotional/informational support, affectionate support, and positive social interactions (but not tangible support) showed more pronounced and consistent mediation for females 75 and older, compared to males or younger age groups. Clinical and health policy interventions targeting specific subtypes of functional social support may be useful in mitigating the negative impacts of depression on cognitive function; these interventions to support cognitive health may be particularly relevant for older females.