Association of IL6 rs1800795 polymorphism with Lithuanian team sports performance

Abstract

Interleukin 6 (IL-6, encoded by the IL6 gene) was the first myokine that was found to be secreted into the blood stream in response to muscle contractions. IL-6 plasma concentration is affected by exercise duration and intensity. The IL6 rs1800795 (-174G>C) polymorphism is a candidate to explain individual variations in exercise related phenotypes such as athletic performance. This study aimed to investigate whether IL6 rs1800795 genotypes are associated with Lithuanian athletes from various sports. The study involved 191 Lithuanian professional athletes representing three functional sports groups (endurance, n = 64; sprint-power, n = 61, and team sports, n = 66) as well as 205 healthy untrained individuals from the Lithuanian population (control samples). Genotyping was performed using TaqMan real-time polymerase chain reaction assay. The results of this case-control association analysis of IL6 rs1800795 (G/C) revealed statistically significant differences in the group of team sports (a more frequent heterozygous CG genotype was detected) compared to the control group (GG/GC/CC: 16.7%, 66, 7%, 16.7% vs. 35.1%, 43.4%, 21.5%, p < 0.01). Binary logistic regression analysis showed that the IL6 GC genotype more than doubled the odds of becoming a professional team sports athlete (OR = 2.6; 95% CI: 1.46-4.67; p < 0.005) compared to the control group. Taken together, the findings of this study suggested that IL6 rs1800795 (GC genotype) is associated with athletic performance in team sports (which require the use of both anaerobic and aerobic faculties of energy production). Replication studies are needed to support our data and to fully understand the relationship between IL6 gene and physical performance of athletes.