We aimed to perform a systematic review and meta-analysis of studies examining the levels of chemokines in peripheral blood of patients with bipolar disorder (BD) and healthy controls. Meta-analysis was based on random-effects models with Hedges' g as the effect size estimate. We included 13 eligible studies (1221 BD patients and 663 controls). The following chemokines were analysed: interleukin-8 (IL-8), monocyte-chemoattractant protein-1 (MCP-1), eotaxin-1, eotaxin-2 and interferon-γ-induced protein 10 (IP-10). The levels of IL-8 (N = 8, g = 0.26, 95%CI: 0.11-0.41, p < 0.001), MCP-1 (N = 8, g = 0.40, 95%CI: 0.18-0.63), eotaxin-1 (N = 3, g = 0.55, 95%CI: 0.21-0.89, p = 0.001) and IP-10 (N = 4, g = 0.95, 95%CI: 0.67-1.22, p < 0.001) were significantly higher in BD patients as compared with controls. Subgroup analyses revealed that elevated levels of IL-8 (N = 5, g = 0.75, 95%CI: 0.42-1.07, p < 0.001) and MCP-1 (N = 4, g = 0.57, 95%CI: 0.28-0.86, p < 0.001) appeared only in BD patients during their depressive phase. Illness duration was associated with significantly lower levels of IL-8 in meta-regression analysis. In turn, elevated levels of IP-10 were present during euthymia (N = 2, g = 0.76, 95%CI: 0.43-1.10, p < 0.001) but not depression (N = 2, g = 1.81, 95%CI: -0.16 to 3.77, p = 0.072). The analysis of eotaxin-1 levels was mainly based on studies of euthymic BD patients (N = 3). Our results suggest that chemokine alterations in BD might be related to mood state. Elevated levels of IL-8 and MCP-1 might be specific to depression. Available evidence indicates that increased levels of eotaxin-1 and IP-10 appear in euthymia; however, more studies are needed to address these alterations in other mood states.

Although the number of studies examining the relationships between sedentary behaviors (SB) and anxiety is growing, an overarching evidence, taking into account children, adolescents, and adults as well as different types of SB and different categories of anxiety outcomes, is still missing. Thus, this systematic review and meta-analysis aimed at obtaining a comprehensive overview of existing evidence. A search in the following databases: PsycINFO, PsycARTICLES, Academic Search Complete, ERIC, HealthSource: Nursing/Academic Edition and MEDLINE, resulted in k = 31 original studies included in the systematic review (total N = 99,192) and k = 17 (total N = 27,443) included in the meta-analysis. Main inclusion criteria referred to testing the SB--anxiety relationship, the quality score (above the threshold of 65%), and the language of publications (English). The study was following the PRISMA statement and was registered at PROSPERO (CRD42017068517). Both the systematic review and meta-analysis indicated that overall average effects were small: higher levels of symptoms of anxiety were associated with higher levels of SB (weighted r = .093, 95% CI [.055, .130], p < .001). Moderator analyses indicated that trends for stronger effects were observed among adults, compared to children/adolescents (p = .085). Further longitudinal studies are necessary to elucidate the predictive direction of the anxiety—SB relationship and to clarify whether the effects depend on the type of anxiety indicators.