Younger women are more susceptible to inflammation: A longitudinal examination of the role of aging in inflammation and depressive symptoms

Abstract

BackgroundThe degree to which effects of inflammation on mood and behavior vary across the lifespan remains relatively unexplored despite well-established, age-related alterations in both the immune and central nervous systems. Further, the implications of this developmental process within different symptom domains warrants careful consideration. MethodsWomen diagnosed with breast cancer (n = 188; ages 27–89) provided blood samples and reported depressive symptoms prior to adjuvant treatment, at the end of adjuvant treatment, and 6-, 12-, and 18-months after completing adjuvant treatment via the CES-D. Blood was assayed for C-reactive Protein (CRP) and interleukin (IL)-6. We used mixed linear effect models to estimate within- and between-person effects of CRP or IL-6 on 4 domains of depressive symptoms: depressed affect, low positive affect, somatic complaints, and interpersonal problems. ResultsHigh average inflammation was associated with elevated somatic complaints (CRP p = .009, IL-6: p = .05), interpersonal problems (CRP p = .002, IL-6 p < .001), and positive affect (IL-6 p = .03), but only among the youngest women in the sample (age 50 or younger). Younger women also reported more depressed affect at assessments when inflammation was higher (CRP p = .045, IL-6 p = .09). ConclusionsThe association between inflammation and specific depressive symptoms is dynamic and varies across the lifespan, which may help clarify apparent inconsistencies in the extant literature as well as inform more precise interventions targeting this pathway.