The association between victimization and inflammation: A meta-analysis

Background: To meta-analyze the existing studies examining the association of childhood and adulthood victimization with inflammation and to explore the moderating variables that affect these relationships. Methods: Relevant work published before 28th February 2021 was identified by searching five major databases. We analyzed the cross-sectional data extracted from cross-sectional and longitudinal studies using the random-effects model to estimate the correlation (r) as the pooled effect size and further conducted subgroup analyses and sensitivity analyses. Results: A total of 37 articles finally met the inclusion criteria, including studies for C-reactive protein (CRP) (k = 23; N_CRP = 11,780), interleukin-6 (IL-6) (k = 31; N_IL-6 = 8943), and tumor necrosis factor-alpha (TNF-α) (k = 14; N_TNF-α = 4125). Overall, victimization has a significantly positive association with inflammation, with a small effect size (r = 0.122). Specifically, effect sizes were the largest for TNF-a (r = 0.152), followed by IL-6 (r = 0.119), and CRP (r = 0.084). Additionally, the effect sizes for victimization against children were r = 0.145 (k = 6) for childhood victimization - childhood inflammation, and r = 0.139 (k = 27) for childhood victimization - adulthood inflammation, which appear to be larger than that of victimization against adults (r = 0.039; k = 2). Limitations: Only a small number of studies on adult victimization were included. In addition, we only analyzed the cross-sectional relationship and did not have sufficient data to compare different types of victimization and single vs. multiple victimizations. Conclusions: Victimization is associated with a heightened inflammatory response. As victimization against children may have a stronger effect than victimization against adults, prevention of victimization targeting the childhood period may be necessary. Studies with more robust methodologies (i.e., representative, longitudinal, and multi-country designs) are needed to confirm these findings and to unpack the underlying mechanisms.