Systematic review of the association between life-course socioeconomic status and late-life cognitive decline

Socioeconomic status (SES) is a potentially important upstream determinant of late-life cognitive health, but a review which captures the dynamic influence of SES across the life-course is lacking. We conducted a systematic review of studies reporting associations between life-course SES and dementia/late-life cognitive decline. On 21 February 2024, we searched Medline, Embase, PsycINFO, CINAHL, British Education Index, Web of Science, Scopus and Advanced Google for studies related to life-course SES and dementia. We included studies employing trajectory or mediation analysis that measured dementia/cognitive decline as outcomes. Two researchers independently screened articles and assessed risk of bias. Results were synthesised narratively and in Harvest plots. We included 18 out of 6040 studies screened (n=7 trajectory studies, n=8 mediation studies, n=3 both). Most (13/23) trajectory analyses reported that stable low SES and downward social mobility, relative to stable high SES/upward mobility, were linked to higher dementia and/or cognitive decline risk. Half (5/10) of the mediation analyses reported full mediation of adulthood SES on the association between childhood SES and dementia/cognitive decline, and 4/10 reported partial mediation. Overall, study quality was moderate. SES has a dynamic life-course association with dementia risk. Increases in dementia risk are compounded by sustained life-course disadvantage. Policies to address socioeconomic disadvantage across the life-course are needed to address this upstream determinant of dementia. CRD42024505975.