title: Association between polymorphism of interleukin-6 in the region -174G/C and tinnitus in the elderly with a history of occupational noise exposure.
abstract: Tinnitus is a symptom usually related to cochlear change that may arise from noise exposure and induces expression of proinflammatory cytokines including interleukin-6 (IL6). This study aimed to evaluate the association between the polymorphism of the IL6 gene in the region 174G/C and tinnitus in elderly with history of occupational noise exposure.
  
  
  METHODS
  This was a cross-sectional study with a sample of 179 independent elderly individuals aged >60 years. Information on exposure to occupational noise was obtained by interviews. Audiological evaluation was performed using pure tone audiometry and genotyped through polymerase chain reaction by restriction fragment length polymorphism (PCR-RFLP). Data were analyzed using the chi-square test and the odds ratio (OR), with the significance level set at 5%. Among the study subjects, 24.6% were homozygous for the G allele, 39.7% were homozygous for the C allele, and 35.8% were heterozygous for IL6 (P > 0.05). Of these, 33.5% reported noise exposure history, with 42.5% having tinnitus. We found significant association between the genotype and allele frequencies of the IL6 -174 gene (rs1800795) and tinnitus among the elderly with history of exposure to occupational noise (P = 0.03). The elderly with the C allele were less likely to have tinnitus associated with history of exposure to occupational noise [OR = 0.167, confidence interval (CI) 95% 0.167-0.749; P = 0.004] when compared to those carrying the G allele. This study suggests that there is an association between polymorphisms in the IL6 gene at region - 174G/C and susceptibility to tinnitus.
authors.forename: Marcelo Yugi
authors.initials: MY
authors.lastname: Doi
authors.forename: Ana Carolina Marcotti
authors.initials: AC
authors.lastname: Dias
authors.forename: Regina Célia
authors.initials: RC
authors.lastname: Poly-Frederico
authors.forename: Maira Gabriela Sasso Rosa
authors.initials: MG
authors.lastname: Maria
authors.forename: Maria Nazaré
authors.initials: MN
authors.lastname: de Oliveira
authors.affiliation: Department of Audiology and Speech Therapy, Centre of Research in Health Sciences, University of Northern Parana, Londrina-PR, Brazil.
authors.forename: Luciana Lozza
authors.initials: LL
authors.lastname: de Moraes Marchiori
mesh_terms: D000368:Aged; D001938:Brazil / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005260:Female; D005787:Gene Frequency; D059647:Gene-Environment Interaction; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D015850:Interleukin-6 / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009623:Noise, Occupational / Q000706:statistics & numerical data*; D016273:Occupational Exposure / Q000706:statistics & numerical data*; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D012150:Polymorphism, Restriction Fragment Length; D014012:Tinnitus / Q000453:epidemiology / Q000235:genetics*
chemical_list: C508600:IL6 protein, human; D015850:Interleukin-6