Background: Fibroblast growth factors (FGFs), particularly FGF19, FGF21, and FGF23, are increasingly recognized for their roles in metabolic regulation. Their potential associations with adiposity markers remain under investigation, with findings from human studies often inconsistent. This systematic review and meta-analysis aimed to determine the associations between circulating levels of these FGFs and adiposity-related indices in adult populations.
Methods: A comprehensive literature search was performed in PubMed, Web of Science, and Scopus up to March 2023. Search terms included FGF19, FGF21, FGF23, and adiposity-related anthropometric indices such as body mass index (BMI), body weight, waist circumference (WC). No restrictions on language or publication date were applied. Additional relevant studies were identified by screening the reference lists. The review protocol was registered with PROSPERO (CRD42023428338). Meta-analyses were conducted using random-effects models, and heterogeneity assessed via the I² statistic.
Findings: Out of 4,319 initial records, 21 studies met the inclusion criteria. Meta-analysis indicated an inverse association between FGF19 and BMI (r = –0.15; 95% CI: –0.26, –0.04; P = 0.010; I² = 26.4%), while its correlation with WC was non-significant (r = –0.16; 95% CI: –0.34, 0.03; P = 0.10; I² = 49.8%). FGF21 showed a consistent positive relationship with body weight (r = 0.20; P = 0.001; I² = 70.8%), BMI (r = 0.22; P < 0.001; I² = 73.2%), and WC (r = 0.31; P < 0.001; I² = 94.7%). Associations between FGF23 and adiposity measures were heterogeneous and inconclusive.
Conclusion: In summary, this meta-analysis supports a significant positive correlation between serum FGF21 levels and BMI, body weight, and WC FGF19 exhibited a modest inverse association with BMI, while no significant association was observed with WC. The variability in the association patterns among FGF subtypes highlights the need for further targeted research.