Background and Objectives: An obesity-related elevated body mass index (BMI) across life is associated with chronic low-grade inflammation and increased levels of C-reactive protein (CRP) in blood. CRP is a marker and promoter of inflammation. The objectives of this study were to examine the effect of obesity on the relationship between peripheral and gingival CRP levels and to examine the effects of gingival CRP levels on gingival fluid inflammatory cytokines in periodontitis-resistant obese individuals. Materials and Methods: Thirty-nine participants in good periodontal health were recruited. Twenty patients were classified as lean and nineteen as obese based on their BMI levels. A thorough periodontal assessment was carried out. Gingival crevicular fluid (GCF) and blood samples were collected. Both GCF and blood samples were analyzed for interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8), tumor necrosis factor-α (TNF-α), interleukin-10 (IL-10), interleukin-17A (IL-17A), and CRP. Results: GCF CRP levels were significantly higher in the obese than in the lean individuals. No statistically significant differences were noted between the two groups in either GCF or blood in terms of any of the inflammatory cytokine levels. IL-17A was not detected in the GCF of most subjects in both groups. GCF CRP levels were positively associated with blood CRP levels, and the association tended to be stronger in the obese individuals. GCF CRP showed no associations with GCF IL-10 in both groups. Although GCF CRP levels were positively associated with multiple GCF inflammatory cytokines (e.g., IL-1β, IL-6, IL-8, and TNF-α) in all subjects, the associations tended to be weaker in the obese individuals (e.g., IL-1β, IL-6, and TNF-α). Furthermore, the levels of the GCF inflammatory cytokines IL-6 and TNF-α were decreased in the obese individuals. Conclusions: Obesity unfavorably influences the relationship between blood and GCF CRP levels and promotes increased CRP levels in GCF. Collectively, the findings suggest a weakened inflammatory cytokine response in the gingival tissues of obese individuals.
Keywords: C-reactive protein; gingival fluid; inflammatory cytokines; obesity.