title: Cortical bone resorption during exercise is interleukin-6 genotype-dependent.
abstract: The objective of this study was to examine the relationship between the interleukin-6 (IL-6) -174 G>C promoter polymorphism and exercise-induced femoral cortical bone resorption. Skeletal response to exercise was assessed in 130 male Caucasian army recruits. Five cross-sectional magnetic resonance images of the right femur were obtained before and after a 10-week period of basic physical training, and changes in cross-sectional cortical area were calculated. Recruits were genotyped for the -174 G>C IL-6 promoter polymorphism. Genotype frequencies (GG 36%, GC 47%, CC 22.17%) were in Hardy-Weinberg equilibrium. The mean percentage change in proximal femoral cross-sectional cortical area was strongly IL-6 genotype-dependent, with GG homozygotes losing 6.8 (3.82)% in cortical area, GC gaining+5.5 (4.88)% and CC gaining+17.3 (9.46)% (P=0.007 for linear trend). These changes persisted throughout the right femur and were significant in the femur as a whole (P=0.03). This study demonstrates an association between a functional polymorphism in the IL-6 gene and femoral cortical remodelling during strenuous physical exercise. Previous studies have suggested an important role for IL-6 in the regulation of bone mass in postmenopausal women, and in the invasion of bone by metastatic tumour deposits. These data extend these observations to the regulation of bone mass in healthy males, supporting a fundamental role for IL-6 in the regulation of bone mass and bone remodelling in humans.
authors.affiliation: Department of Cardiovascular Genetics, BHF Laboratories at UCL, Rayne Building, Royal Free and University College Medical School, 5 University Street, London, UK.
authors.forename: Sukhbir S
authors.initials: SS
authors.lastname: Dhamrait
authors.forename: Laurence
authors.initials: L
authors.lastname: James
authors.forename: David J
authors.initials: DJ
authors.lastname: Brull
authors.forename: Saul
authors.initials: S
authors.lastname: Myerson
authors.forename: Emma
authors.initials: E
authors.lastname: Hawe
authors.forename: Dudley J
authors.initials: DJ
authors.lastname: Pennell
authors.forename: Michael
authors.initials: M
authors.lastname: World
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Humphries
authors.forename: Fares
authors.initials: F
authors.lastname: Haddad
authors.forename: Hugh E
authors.initials: HE
authors.lastname: Montgomery
mesh_terms: D000328:Adult; D015519:Bone Density / Q000235:genetics*; D001862:Bone Resorption / Q000235:genetics* / Q000378:metabolism; D015444:Exercise; D005269:Femur / Q000378:metabolism / Q000503:physiopathology*; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D005838:Genotype; D006801:Humans; D015850:Interleukin-6 / Q000235:genetics* / Q000378:metabolism; D008297:Male; D008889:Military Personnel; D011110:Polymorphism, Genetic; D006113:United Kingdom
chemical_list: D015850:Interleukin-6