Effects of Mind-Body Interventions on Immune and Neuroendocrine Functions: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Objective: Chronic stress affects the immune system via the hypothalamic-pituitary-adrenal (HPA) axis and autonomic system. Chronic inflammation is a risk factor for cardiovascular diseases, cancer onset and progression, susceptibility to infection, and cognitive impairment. Mind-body interventions (MBIs) could affect the immune and neuroendocrine systems, and we aimed to assess the correlations among these systems through a meta-analysis. Methods: RCTs were identified by searching three databases: PubMed, Embase, and Scopus. Of the 1697 studies identified, 89 were included in this study. Risk of bias was examined using the Cochrane risk-of-bias assessment tool. Data were pooled using a random-effects model, and SMDs were calculated. I2 statistics and Egger's test were used to assess the significance of the asymmetry. Influence diagnostics were used to assess whether pooled effects were disproportionately dependent on any single study. The trim-and-fill method was applied to all identified asymmetric instances. Meta-regression was used to examine the moderating effect of MBI efficacy on biomarkers. Results: MBIs generally decreased the levels of inflammatory factors, such as the CRP, IL-6, TNF-alpha, IL-1, IL-8, IL-17, ESR, and cortisol, and increased IL-10, IFN-gamma, IL-1ra, BDNF, and secretory IgA. In a subgroup analysis of the CNS and cancer, qigong and yoga showed increased BDNF and IL-6, respectively. Notably, IL-10 was increased in inflammatory diseases, and IFN-gamma was increased in viral infections. Conclusions: This study revealed MBIs decrease inflammatory cytokine and increase anti-inflammatory, antiviral, and immune-activating factors. These results suggest the MBIs including gentle physical exercise may be beneficial for neuropsychiatric disorders or tumors. Prospero registration number: CRD42024507646.