The combined frequencies of the IL-6 G-174C and IGFBP3 A-202C polymorphisms among swimmers and runners

Abstract Previous studies have demonstrated that compared to runners, swimmers carry a higher prevalence of the IL-6 -174C polymorphism and lower single nucleotide polymorphism frequencies of the IGF system. Purpose The aim of the present study was to assess the combined frequency of the IL-6 -174G/C and IGFBP3 -202A/C polymorphisms among track and field athletes and swimmers. Methods Track and field athletes were divided into long-distance runners (major event 5000 m-marathon, n = 63) and power athletes (major event 100-200 m sprints and long jump, n = 67). Swimmers were divided into long-distance swimmers (major event: 400-1500 m, n = 50), and short-distance swimmers (major event: 50-100 m, n = 43). All participants had achieved results that ranked them among the top all-time Israeli athletes in their event, and competed at national and/or international level on a regular basis. Results Carrying both IL-6C and IGFBP3C mutations was significantly greater among long-distance swimmers (LDS – 44%) compared to long distance runners (LDR – 21%, p  Conclusion The prevalence of carrying both IL-6C and IGFBP3C mutations was significantly higher among the swimmers compared to runners. It is possible that carrying the IGFBP3C polymorphism is required to compensate for the potential genetically non-beneficial effects of a higher IL-6C genotype and an attenuated IGF system among the swimmers.