Inflammation is associated with future depressive symptoms among older adults

Abstract

Inflammation has been reliably associated with depression. However, the directionality of this association is poorly understood, with evidence that elevated inflammation may promote and precede the development of depression, as well as arise following its expression. Using data from older adults ( N ​= ​1,072, ages 60–73) who participated in the ongoing longitudinal St. Louis Personality and Aging Network (SPAN) study, we examined whether inflammatory markers (interleukin-6: IL-6, C-reactive protein: CRP, and tumor necrosis factor α: TNFα) and depression were prospectively predictive of one another. Fasting serum samples and self-reports of depressive symptoms (Beck Depression Inventory-II) were obtained from participants at 2 sessions approximately 2 years apart. Structural equation models as well as regressions that accounted for a host of potentially confounding covariates and depression at baseline revealed that baseline IL-6 and CRP, but not baseline TNFα were associated with elevated depressive symptoms at the follow-up session (IL-6: β ​= ​0.080, p ​= ​0.036; CRP: β ​= ​0.083, p ​= ​0.03; TNFα: β ​= ​0.039, p ​= ​0.314). However, there was no association between baseline depressive symptoms and follow-up inflammatory markers (βs ​= ​−0.12 to −0.006, all p s ​> ​0.05). Collectively, these data suggest that inflammation prospectively predicts depression, but depression does not predict inflammation in older age. These data add to a growing literature suggesting that inflammatory signaling may plausibly promote the development of depression.

C-Reactive Protein and Specific Depression Symptoms Among Older Adults: An Exploratory Investigation of Multi-Plane Networks Using Cross-Sectional Data From NHANES (2017–2020)

“…Depression is a debilitating condition among older adults that can adversely affect functional ability, quality of life, and overall health status. Although the underlying pathophysiology of depression is not yet entirely understood, there is accumulating evidence supporting the role of inflammatory proteins in increasing depression risk in this population (Bell et al, 2017; Bondy et al, 2021; Song et al, 2015). Among these proteins, C-reactive protein (CRP), an acute-phase reactant released from the liver in response to elevated cytokine levels, is arguably the most extensively studied.…”

Borderline personality pathology, health behavior, and inflammation: Potential behavioral and biological mechanisms underlying childhood physical abuse and age-related disease

“…As a result of meta-analytic evidence that CRP is not associated with childhood physical abuse (Baumeister, et al, 2016) as well as the lack of an association between childhood physical abuse and CRP after accounting for covariates in our sample, we did not include CRP in our mediational models. Suggestive of unique associations between borderline pathology and both IL-6 and CRP, these associations were robust to the additional inclusion of either childhood abuse (IL-6: β= 0.11, p=0.004; CRP: β= 0.11, p=0.005) or depression (IL-6: β= 0.07, p=0.02; CRP: β= 0.06, p=0.05, which was also uniquely associated with inflammation; Supplemental Figure 2; Bondy et al, 2021) in the model. However, consistent with the mediational model presented below, the association between childhood physical abuse and IL-6 was not robust to the inclusion of borderline pathology (β=0.009, p=0.83).…”

Biomarkers common for inflammatory periodontal disease and depression: A systematic review

“…One prospective study on young individuals did indicate that depression episodes increased CRP levels and as such may be considered an inflammatory promoter ( Copeland et al., 2012 ). More evidence is suggesting the role of inflammation in subsequent development of depression ( Bondy et al., 2021 ). Still, a range of other comorbid factors are accountable for an increase in systemic inflammation in patients with depression.…”