Interleukin-6 genotype is associated with high-density lipoprotein cholesterol responses to exercise training.

Background: High-density lipoprotein cholesterol (HDL-C) and its subfractions are modifiable with exercise training and these responses are heritable. The interleukin-6 (IL6)-174G/C polymorphism may be associated with HDL-C levels. We hypothesized that the IL6-174G/C polymorphism would be associated with plasma HDL-C response to exercise training.
Methods and Results: Sixty-five 50- to 75-year-olds on a standardized diet were studied before and after 24 weeks of aerobic exercise training. Significant differences existed among genotype groups for change with exercise training in HDL-C, HDL3-C, integrated HDL4,5NMR-C, and HDLsize. The CC genotype group increased HDL-C more than the GG (7.0 +/- 1.3 v. 1.0 +/- 1.1 mg/dL, p = 0.001) and GC groups (3.3 +/- 0.9 mg/dL, p = 0.02); for HDL3-C, the CC group increased more than the GG (6.1 +/- 1.0 v. 0.9 +/- 0.9, mg/dL p < 0.001) and GC groups (2.5 +/- 0.7 mg/dL, p = 0.006). Integrated HDL4,5NMR-C increased more in the CC than GG group (6.5 +/- 1.6 mg/dL v. 1.0 +/- 1.3 mg/dL, p = 0.01), as did HDLsize compared to the GG (CC: 0.3 +/- 0.1 v. GG: 0.1 +/- 0.1 nm, p = 0.02) and GC (0.0 +/- 0.0 nm, p = 0.007) groups.
Conclusions: IL6 genotype is associated with HDL-C response to exercise training.