The Association between IL6-174 G/C Gene Polymorphism and Obesity: A Systematic Review and Meta-analysis

Background: The interaction between genetic and environmental factors has resulted in growing prevalence of obesity around the world. IL6-174 G/Cgene polymorphism is widely studied as the involved factor in developing obesity. Objectives: The aim of the present study is to evaluate the relationship between Interleukin 6-174 G/C promoter gene polymorphism and obesity in a systematic review and meta-analysis study. Methods: In the present study Science Direct,Medline, Embase, Google Scholar, PubMedand SID search engines have been searched until March 2016. Articles were evaluated using the key words IL6 plus polymorphism or mutation or variant and adiposity, BMI and obesity. Data was analyzed using STATA software (12th version). OR ratio was calculated with 95% confidence interval to evaluate the strength in link between IL6 gene and obesity. Heterogeneity was calculated using I2 test. Articles bias was evaluated using funnel plot versus standard error (SE). The asymmetrydegree of the funnel plot was tested using linear regression tests ofEgger s and Begg s. Results: Generally, 12 articles entered systematic review and 6 articles entered final meta-analysis. After data was extracted, the total case group consisted of 5343 people and control group consisted of 3449 people. The odds ratio was estimated for additive model CC vs GC (OR= 1; CI: 95%: 0/9-1/12), recessive model CC + GC vs GG (OR= 1/04; CI: 95%: 0/95- 1/15) and for dominant model (OR= 1/10; CI: 95%: 1-1/21). Also the results showed that there is a statistically significant relationship between IL-61-74 G/C gene polymorphism and obesity (P 0/05). Conclusion: Generally, the results of the present study show that the IL-6 -174 G/C gene polymorphism is related to the obesity.