The Acute Inflammatory Effects of Weight Stigma: An Experimental Pilot Study

Weight stigma is a chronic stressor and may contribute to cardiometabolic health risk. This pilot study tests an experimental protocol exploring acute inflammation as a potential biological mechanism connecting weight stigma and disease risk. Preliminary effect sizes and protocol feasibility were assessed. Women (N=44, 68% white) with overweight/obesity (M _BMI =33.2±6.7 kg/m²) were randomized to either weight stigma (n=22) or control (n=22) stress reactivity tasks. Serum cytokines (interleukin [IL]-6, tumor necrosis factor [TNF]-α, interferon [IFN]-γ) were measured at baseline and serially over 90 minutes via peripheral intravenous catheter (PIVC) to assess inflammatory responses. The absolute change (Δ; baseline-to-peak) and incremental area under the curve (AUC_i) were calculated for all outcomes. Within the weight stigma group, pre/post-task increases in IL-6 (d=.20, p=.365), TNF-α (d=.43, p=.047), and IFN-γ (p=.078, d=.48) were consistent with small effects. Within the control group, only IL-6 increased and displayed a medium effect (d=.62, p=.004). When comparing weight stigma versus control, the between-group difference in ΔTNF-α displayed a small effect (d=.21, p=.495), consistent with a greater TNF-α increase in weight stigma. Similarly, a small effect size was observed for weight stigma displaying greater ΔIFN-γ (d=.46, p=.153) and IFN-γ AUC_i (d=.27, p=.502) versus control. Experimental procedures were feasible to conduct with minimal attrition/data loss. Based on the small effect sizes observed in this pilot study, the impact of weight stigma on acute inflammatory responses warrants further investigation in larger samples. Use of in-lab weight stigma stress tasks with repeated blood draws via PIVC was supported as a feasible future protocol.