Patients: Patients undergoing screening colonoscopy in the Abant Izzet Baysal University Hospital Gastroenterology Polyclinics between years 2010 and 2013 were selected for study. Antropometric measurements were performed by trained medical stuff. Patients who were smoking, known diabetes mellitus, chronic renal disease, chronic hepatic disease, malignancy, hypertension, colitis, colorectal surgery and previously performed colonoscopic examination were excluded from this study. Subjects were grouped according to whether adenoma is present or not. Study has been performed in accordance with ethical standards as laid down in the 1964 Declaration of Helsinki and its later amendments. The study protocol was approved by Düzce University Ethic Comity. Written informed consent was taken from all participants.
Biochemical analysis: All blood samples were obtained after fasting in the morning and centrifuged for 10 min at 1200 g. Serum specimens were stored at -70ᵒC until laboratory analysis. Equal procedures were used in collection, handling, transport and storage of all samples to standardize preanalytical factors which could affect laboratory assessment. Laboratory analyses of samples were performed simultaneously. Resistin and Adiponectin concentrations were measured by enzyme linked immunosorbent assay (ELISA) according to the manufacturer’s instructions (BioVendor Laboratomi medicina a.s., Brno, Czech Repulic). Detection range of the Resistin was 0.012-50 ng/mL. Intra-assay and inter-assay precision were % CV: < 5,2 % and < 7 %, respectively. Detection limit of the Adiponectin was 0,47 ng/mL. Intra-assay and inter-assay precision were % CV: < 3,3 % and < 5,8 %, respectively. Apellin-12 concentrations were measured by ELISA according to the manufacturer’s instructions (Phoenix Pharmaceuticals, Inc., California, USA). Minimum detectable dose of Apellin-12 was 0,05 ng/mL. Intra-assay and inter-assay precision were %CV: <10 % and <15 %, respectively. Insulin concentrations were measured by ELISA according to the manufacturer’s instructions (DiaMetra S.r.I. Headquater, Segrate, Italy). Minimum detectable dose of insulin is 0.25 µIU/mL. Intra-assay and inter-assay precision were CV (%): <5 % and <10 %, respectively.
Determinations of serum glucose, total cholesterol, HDL and LDL concentrations were measured via colorimetric methods with autoanalysers according to manufacturer's instructions. (Architect c 8000, Abbot Laboratories, USA). We measured total Hb A1c by cation-exchange chromatography (MQ-2000PT, Shanghai Hui Zhong Medical Technology Co.Ltd). This method was traceble with referance method of IFCC.
Colonoscopic examination: Bowel preparation was done with polyethylene glycol. Colonoscopy was performed by an experienced gastroenterologist. The colonoscope was inserted up to ileocecal valve under conscious sedation with midazolam.
Pathologic examination: All specimens were analysed in patalogy department. All paraffin blocks were stained with heamotoxilen and eosin staining and evaluated under light microscope. Adenomatous polyps were grouped as; tubuler, tubulovillous and villous. Adenomatous polyps were grouped as severe, moderate and mild dysplasic; so as to assess the risk of colon cancer development.
Statistical analysis: Kolmogorow-Smirnov test were used for testing normality distribution of numerical properties of data’s. The relation between the presence of adenoma and other risk factor were done with univariate analysis. Comparisons of parameters between groups either normally distributed or not were done with Independent Sample-t test or Mann-Whitney U test respectively. The relation between presence of adenoma and categorical variables were evaluated with Pearson ki-square test. For multiple comparisons nonparametric Kruskall Wallis test was used. P<0.05 was accepted statistically significant. PASW (version 18) was used for statistical analysis.