title: Effects of 174 G/C polymorphism in the promoter region of the interleukin-6 gene on plasma IL-6 levels and muscle strength in elderly women.
abstract: We investigated the effect of -174 G/C single-nucleotide polymorphism in the promoter region of the IL6 gene on plasma IL-6 levels and muscle strength, and the relationship between IL-6 levels and muscle strength in elderly women. The sample consisted of 199 elderly residents (73.0 ± 7.8 years old) from rest homes and the community in Belo Horizonte, MG, Brazil. -174 G/C polymorphism was determined by direct sequencing of the product by PCR, and plasma IL-6 concentrations were measured by ELISA. Muscle strength in the knee joint was evaluated using a Biodex System 3 Pro® isokinetic dynamometer. ANCOVA was used to determine the effect of polymorphism on IL-6 levels and muscle strength, and the Pearson correlation coefficient to assess the relationship between IL-6 levels and muscle strength. -174 G/C polymorphism was associated with the plasma IL-6 levels of elderly women (P < 0.01) since homozygotes for the G allele showed high IL-6 levels (GG 3.85 pg/mL, GC + CC 2.13 pg/mL). There was no association of polymorphism on muscle strength (P > 0.05). No association was found between IL-6 levels and knee extensor muscle (r = 0.087, P = 0.306) or flexor (r = -0.011, P = 0.894) strength. An interaction between -174 G/C polymorphism and housing conditions of the sample of elderly women was identified, with the effect of genotype on IL-6 levels being higher in the institutionalized elderly. These results support the evidence that -174 G/C polymorphism of the IL6 gene associates with individual variability of plasma IL-6 levels in elderly women.
authors.affiliation: Programa de Pós-Graduação em Ciências da Reabilitação, Departamento de Fisioterapia, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, Belo Horizonte, MG, Brazil.
authors.forename: D S
authors.initials: DS
authors.lastname: Pereira
authors.forename: D M
authors.initials: DM
authors.lastname: Garcia
authors.forename: F M S
authors.initials: FM
authors.lastname: Narciso
authors.forename: M L A S
authors.initials: ML
authors.lastname: Santos
authors.forename: J M D
authors.initials: JM
authors.lastname: Dias
authors.forename: B Z
authors.initials: BZ
authors.lastname: Queiroz
authors.forename: E R
authors.initials: ER
authors.lastname: Souza
authors.forename: O T
authors.initials: OT
authors.lastname: Nóbrega
authors.forename: L S M
authors.initials: LS
authors.lastname: Pereira
mesh_terms: D000368:Aged; D003430:Cross-Sectional Studies; D004797:Enzyme-Linked Immunosorbent Assay; D005080:Exercise Test; D005260:Female; D005838:Genotype; D006801:Humans; D015850:Interleukin-6 / Q000097:blood* / Q000235:genetics*; D007537:Isometric Contraction; D007719:Knee Joint; D053580:Muscle Strength / Q000235:genetics*; D011110:Polymorphism, Genetic / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012959:Socioeconomic Factors
chemical_list: D015850:Interleukin-6