The association of interleukin-18 genotype and serum levels with metabolic risk factors for cardiovascular disease

Abstract

AbstractObjectiveCirculating levels of interleukin (IL)-18 are associated with the metabolic syndrome and risk for the development of cardiovascular disease (CVD). This study investigated the association between the circulating IL-18 levels and the −137 G/C polymorphism within theIL-18gene with metabolic risk factors for CVD in normal-weight and obese black South African women.MethodsBlood pressure (BP), body composition (dual-energy X-ray absorptiometer), visceral adiposity (computerized tomography), as well as fasting glucose, insulin, lipid profile, IL-18 levels, andIL-18genotype were measured in 104 normal-weight (body mass index (BMI) ≤25 kg/m2) and 124 obese (BMI≥30 kg/m2) black South African women.ResultsSubjects with a GC genotype (23%) had a greater mean arterial pressure (MAP, 90.6±11.1 vs 85.5±10.3 mmHg,P<0.001) than the subjects with the GG genotype. Serum IL-18 levels were not associated with IL-18 genotype (P=0.985); however, they significantly correlated with percentage of body fat (r=0.25,P<0.001), visceral adiposity (r=0.32,P<0.001), MAP (r=0.22,P=0.001), HOMA-IR (r=0.33,P<0.001), fasting insulin (r=0.25,P<0.001), triglyceride (r=0.16,P<0.05), and high-density lipoprotein-cholesterol (r=−0.14,P<0.05) levels, after adjusting for age and body fatness.ConclusionsWe show for the first time that the GC genotype of theIL-18−137 G/C polymorphism and the circulating IL-18 levels are independently associated with raised BP. Moreover, fasting IL-18 levels are associated with the other metabolic risk factors for CVD in normal-weight and obese black South African women.