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; NCRP = 11,780), interleukin-6 (IL-6) (k = 31; NIL-6 = 8943), and tumor necrosis factor-alpha (TNF-α) (k = 14; NTNF-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.