title: The correlation of serum and gingival crevicular fluid cytokines in obese subjects.
abstract: OBJECTIVE
  To investigate the correlation between the gingival crevicular fluid (GCF) levels of IL-6 and TNF-alpha with the levels in serum in obese patients.
  
  
  METHODS
  Twenty-six obese adults (BMI > or = 30, age 33-74) provided serum and GCF samples. Smokers and uncontrolled diabetics (HbA1c > 8%) were excluded. Serum and GCF samples were analysed for IL-6 and TNF-alpha using commercially available ELISA kits. Within each subject GCF was collected from two healthy sites (n = 26 subjects) and two gingivitis sites, defined by bleeding on probing (n = 22 subjects). The levels of IL-6 and TNF-alpha in the GCF were compared and correlated with the levels found in serum using Spearman's correlation analysis. A Bland-Altman analysis was used to determine the level of agreement between serum and GCF samples.
  
  
  RESULTS
  IL-6 was more frequently detected than TNF-alpha. This was consistent in serum (100% vs 64%) and GCF samples from healthy (73% vs 52%) and gingivitis (95% vs 36%) sites. There were no significant correlations between the TNF-alpha in serum and GCF samples from healthy (r = 0.27, p = 0.22) and gingivitis (r = -0.19, p = 0.40) sites. In contrast, positive correlations were found for IL-6 between serum and GCF samples from healthy (r = 0.48, p = 0.03) and gingivitis (r = 0.79, p = 0.0001) sites. The correlation and agreement was strongest for IL-6 between serum and gingivitis GCF samples.
  
  
  CONCLUSIONS
  The results of this pilot study suggest a lack of correlation and poor agreement between serum and GCF samples in obese subjects. Studies examining the link between periodontitis and obesity should consider collecting both serum and GCF.
authors: Discipline of Periodontics, Faculty of Dentistry, University of Sydney, Australia. rob@perio-implants.com.au
authors: Robert A
authors: RA
authors: Fell
authors: Kwan-Yat
authors: KY
authors: Zee
authors: Manish
authors: M
authors: Arora
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D003627:Data Interpretation, Statistical; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000150:complications / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005883:Gingival Crevicular Fluid / Q000737:chemistry*; D005891:Gingivitis / Q000097:blood / Q000150:complications / Q000378:metabolism*; D006801:Humans; D015850:Interleukin-6 / Q000032:analysis / Q000097:blood / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000150:complications / Q000378:metabolism*; D010518:Periodontitis / Q000097:blood / Q000150:complications / Q000378:metabolism*; D010865:Pilot Projects; D018709:Statistics, Nonparametric; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis / Q000097:blood / Q000378:metabolism*
chemical_list: D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha