Tumour Necrosis Factor Alpha and Atherogenic Index as Predictors of Insulin Resistance and Risks of Cardiovascular Disease among Obese Subjects in Calabar, Nigeria

Master's Thesis from the year 2016 in the subject Medicine - Internal Medicine, grade: A, University of Calabar, course: Chemical Pathology/Immunology, language: English, abstract: Several studies in different population indicate that inflammation may be the link between obesity, insulin resistance and cardiovascular disease. However, this relationship has not been adequately explored in our population and among Africans with increasing high rate ofobesity and IR. In this study, the association between obesity markers (Body mass index, waist circumference, and waist-hip ratio), inflammatory marker (Tumour necrosis factor-alpha), insulin resistance markers (Homeostasis model assessment of insulin resistance, insulin) and markers of cardiovascular risks (Atherogenic index of plasma, lipid profile, blood pressure) were evaluated in a total of one hundred and sixty subjects (160). One hundred and ten (110) of which were obese subjects (BMI 30kg/m2 and above) and fifty (50) non-obesecontrols. Blood pressure and fasting samples were collected. Anthropometric parameters were measured; body mass index and waist-hip ratio were calculated for all the participants recruited in this study. Obese subjects were further grouped based on their BMI values as; class I (BMI 30-34.9kg/m2), class II (BMI 35-39.9kg/m2) and class III (BMI 40kg/m2 and above). TNF-a and insulin were determined using enzyme linked immunosorbent assay (ELISA). Total cholesterol and triglyceride were determined using the enzymatic colorimetric method; LDL, VLDL, HOMA-1R, AIP were respectively calculated. High density lipoprotein was determined using the precipitation/cholesterol enzymatic method. The mean values of TNF-a, insulin, FPG, HOMA-1R, TC, TG, LDL, VLDL, AIP, SBP and DBP were all significantly higher in obese subjects compared to non-obese controls group (P<0.05). The mean value of HDL was significantly higher in the non-obese controls compared to the obese group (P<0.05). The values of WHR, TG, VLDL, DBP and AIP were significantly higher in male obese subjects compared to obese female (P<0.05). No significant differences were observed in the other parameters in the male and female obese participants. There were no significant variations in the levels of TNF-a, TC, TG, HDL, LDL, VLDL and AIP among the three groups (P>0.05). Insulin and HOMA-1R were significantly higher in class III group compared to the class I group. A significant positive correlation was observed between obesity markers (BMI, WC) and markers of insulin resistance (HOMA-1R, insulin) among the obese subjects (P<0.05).