Obesity and
periodontal diseases have been investigated to be interconnected, but the molecular mechanism underlying this association is still not clear. The aim of this systematic review is to assess the association of serum, salivary and gingival crevicular fluid (GCF) inflammatory markers (IMs),
obesity, and
periodontitis. Studies that evaluated IM of adults according to
obesity status (O) and
periodontitis status (P) (O+P+; O-P+; O+P-) were screened on several electronic databases and grey literature up until February 2019. Risk of bias assessment and level of evidence were evaluated through Fowkes and Fulton scale and Grading of Recommendations Assessment, Development and Evaluation (GRADE). Meta-analyses were grouped according to the biological matrix studied (serum/GCF) and groups (O+P+ vs. O-P+/O+P+ vs. O+P-). Out of the 832 studies screened, 21 were considered in qualitative synthesis and 15 in quantitative synthesis (meta-analysis). Although included studies showed mostly "no" or "minor" problems during the quality assessment, GRADE assessment indicated very low to moderate level of evidence based on the question answered. O+P+ adults exhibited significantly higher serum levels of
C-reactive protein (CRP),
interleukin 6 (IL-6),
leptin, and
tumor necrosis factor-α (
TNF-alpha) and higher
resistin GCF levels than O-P+. O+P+ adults showed significantly higher serum levels of
IL-6 and
leptin and lower
adiponectin serum levels than O+P-. Only qualitative information could be obtained of the IM vaspin, omentin-1, chemerin,
IL-10,
progranulin, MCP-4, IL-1β, and
interferon-γ (IFN-γ).
Obesity and
periodontitis, together or separately, are associated with altered serum and GCF levels of CRP,
IL-6,
leptin,
TNF-alpha,
adiponectin, and
resistin. It was not possible to evaluate the association between
obesity and
periodontitis at salivary levels. The role of recently investigated
biomarkers as vaspin, omentin-1, chemerin,
IL-10,
progranulin, MCP-4, IL-1β, and IFN-γ, which can be key points underlying the association between
obesity and
periodontitis, remains to be further investigated.