Evaluation of tumor necrosis factor alpha, insulin, and homeostasis model assessment of insulin resistance among obese participants living in Calabar, Nigeria

Abstract

Objective: Several studies in different population indicate that inflammation may be the link between obesity and insulin resistance (IR). However, this relationship has not been adequately explored in our population and among Africans with increasing high rate of obesity and IR. This study aims to evaluate the association among obesity markers, tumor necrosis factor-alpha (TNF-α), and markers of IR in obese and nonobese adults living in Calabar, Nigeria. Materials and Methods: A total of 160 participants were recruited for the study: 110 obese participants and 50 nonobese control participants. Anthropometric parameters and blood pressure were measured; body mass index, waist-hip ratio and homeostasis model assessment of IR (HOMA-IR) were calculated for all the participants recruited in this study. Fasting plasma glucose was determined using glucose oxidase method; TNF-α and insulin were determined using enzyme-linked immunosorbent assay. Results: The mean values of TNF-α, insulin, fasting plasma glucose (FPG) and HOMA-IR were significantly higher in obese participants compared to the nonobese control group (P = 0.01). Insulin and HOMA-IR were significantly higher in Class III group compared to the Class I group. A significant positive correlation was observed between obesity markers and markers of IR among the obese participants. There was also a positive correlation between systolic blood pressure and HOMA-IR (r = 0.258) among the obese participants. Conclusion: Findings from the study suggest that obesity is a strong predictor of IR which in turn predicted cardiovascular risk factors such as high blood pressure.