Chronic low-level inflammation in childhood obesity: systematic review and meta-analysis of key biomarkers

Childhood obesity is associated with chronic low-level inflammation, which is considered a key mechanism in the development of insulin resistance, dyslipidemia and increased cardiovascular risk. Increased levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), C-reactive protein (CRP) and high-sensitivity CRP (hs-CRP) have been reported in children with obesity, but research results are contradictory, and pooled quantitative estimates of the levels of these biomarkers for the pediatric population have not yet been conducted.

The aim of the study was to systematize data on inflammatory biomarkers in children with obesity and to compare their levels quantitatively with control groups.

A systematic search of publications was conducted in the databases PubMed, Scopus, Web of Science, Semantic Scholar, e-Library and Google Scholar (until August 2025). Observational studies were included in children and adolescents aged 6–18 years with obesity diagnosed according to WHO criteria or national standards, which reported levels of CRP, hs-CRP, IL-6 or TNF-α.

The meta-analysis included 21 studies with a total of 11,193 participants. Children with obesity showed a significant increase elevated levels of all the inflammatory cytokines studied. The most pronounced difference was noted for CRP, g = −1.30 (95% CI: −2.32; −0.29), whereas hs-CRP, g = −0.70 (95% CI: −1.01; −0.39), IL-6, g = −0.51 (95% CI: −0.80; −0.21) and TNF-α, g = −0.60 (95% CI: −0.97; −0.24) demonstrated moderate, but stable and significant effects.

To our knowledge, this is the first meta-analysis to summarize data on inflammatory cytokines in children with obesity. hs-CRP showed a more moderate effect size but more stable and reproducible results which make it suitable for clinical use. Importantly, these findings gain additional significance when viewed in the context of studies in adolescents, adults, and the elderly, where dynamic of inflammatory cytokines are associated with subclinical vascular changes, cardiovascular events, and mortality. Elevated levels of these markers in childhood may serve as an early biological signal of long-term cardiometabolic risk.

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