Association of interleukin-18 gene polymorphism with body mass index in women

BACKGROUND: Interleukin (IL)-18 is an important regulator of innate and acquired immune responses and has multiple roles in chronic inflammation and autoimmune disorders. Obesity is characterized by low- grade chronic inflammation. IL-18 has been suggested as an adipogenic cytokine that is associated with excess adiposity. The purpose of this study is to evaluate the relationship between IL-18 gene polymorphisms (−137 G/C and −607 C/A) and obesity. METHODS: All 680 subjects were genotyped for the polymorphisms of IL-18 gene promoters (at positions −137 G/C and −607 C/A) using a polymerase chain reaction (271 cases with BMI ≥25 kg/m(2) and 409 controls with BMI <25 kg/m(2)). A chi-square test was used to compare the genotype and allele frequencies between the cases and control populations. RESULTS: Analyses of the genotype distributions revealed that IL-18 –607 C/A polymorphism was associated with an increase in body mass index in obese women in the Korean population (chi(2) = 12.301, df = 2, p = 0.015). CONCLUSION: Carriage of the A allele at position −607 in the promoter of the IL-18 gene may have a role in the development of obesity.