Measurement invariance of the Center for Epidemiological Studies-Depression scale and associations with genetic risk in older adults

Abstract

Background: Center for Epidemiological Studies-Depression scale (CES-D) is widely used self-report measure for assessing depressive symptoms. However, few studies have formally assessed whether the CES-D and its short forms can be used to compare scores in cognitively unimpaired versus cognitively impaired persons and across different age cohorts in old age. We examined the factor structures of 20-, 15-, and 8-item CES-D scales and their measurement invariance for cognitive status and age and associations with cohort, cognitive impairment, and genetic risk of depression.Methods: Participants were from a population-based older Finnish Twin Cohort study including 71–79-year-olds from the MEMTWIN II (n=1698) and 90+ year-olds from the NONAGINTA (n=134) sub-studies. Exploratory factor analyses were performed in MEMTWIN II and confirmatory factor analyses in both cohorts. Cognitive status comparisons and associations with polygenic risk score of major depressive disorder (MDD-PRS) were conducted in MEMTWIN II. Cohort comparisons were performed between MEMTWIN II and NONAGINTA.Results: Exploratory factor analyses (n=1034) suggested four- (CES-D 20) and three-factor (CES-D 8) structures and these models fit the data well in confirmatory analyses (n=664). Unidimensional models had a good (CES-D 15 & 20) or fair fit (CES-D 8). Measurement invariance testing supported scalar invariance of all CES-D versions for cognitive status and age. NONAGINTA participants had significantly more depressive symptoms than MEMTWIN II participants. Higher MDD-PRS was significantly associated with more depressive symptoms in different CES-D versions.Discussion: The measurement properties of the CES-D indicate that different versions are measuring depressive symptoms similarly across the cohorts and cognitive spectrum in old age. Thus, even the short CES-D appears to be a psychometrically adequate tool to assess depressive symptoms in old age including those over 90 years old and those with cognitive impairment. Higher MDD-PRS and older age predicted greater depressive symptoms in old age.