title: Acoustic parameters and salivary IL-6 levels in overweight and obese teachers.
abstract: OBJECTIVE
  Either obesity or vocal loading task leads to elevation of proinflammatory cytokines such as interleukin 6 (IL-6). However, it is unknown whether vocal parameters after vocal loading are correlated with body mass index (BMI) or IL-6. We hypothesize that vocal loading induces an elevation of acoustic parameters of voice and salivary IL-6 in overweight and obese people.
  
  
  METHODS
  A total of 33 schoolteachers without any self-reported voice alterations were invited to participate in this study. Participants were classified according to BMI into normal, overweight, and obese groups. The vocal loading task consisted of loud speech (60-90 minutes) in their classroom. Salivary and voice samples were taken before and after vocal loading. Perceptual and self-reported voice alterations and objective voice analyses were investigated. The relative concentration of salivary IL-6 was estimated by a colorimetric assay.
  
  
  RESULTS
  Obese teachers showed a significant elevation in fundamental frequency value after vocal loading. In addition, reduction in harmonics-to-noise ratio (HNR) was observed in teachers with normal weight after vocal loading but not in overweight or obese groups. No significant correlation was observed between BMI and any of the acoustic parameters analyzed or salivary IL-6 levels. Furthermore, teachers who were overweight showed a significant increase in the salivary IL-6 levels after vocal loading. Interestingly, salivary IL-6 levels were positively correlated with HNR value in the overweight group after vocal loading.
  
  
  CONCLUSIONS
  Excessive body weight is related to alterations in fundamental frequency and HNR. In addition, HNR, but not BMI, is associated with salivary IL-6 levels in overweight teachers.
authors: Department of Basic Sciences, Faculty of Sciences, Vascular Physiology Laboratory, Group of Investigation in Tumor Angiogenesis (GIANT), Group of Research and Innovation in Vascular Health (GRIVAS Health), University of Bío-Bío, Chillán, Chile; School of Phonoaudiology, Universidad Pedro de Valdivia, Chillan, Chile.
authors: Jesenia
authors: J
authors: Acurio
authors: School of Phonoaudiology, Universidad Pedro de Valdivia, Chillan, Chile.
authors: Cristian
authors: C
authors: Celis
authors: School of Phonoaudiology, Universidad Pedro de Valdivia, Chillan, Chile.
authors: Jazmin
authors: J
authors: Perez
authors: Department of Basic Sciences, Faculty of Sciences, Vascular Physiology Laboratory, Group of Investigation in Tumor Angiogenesis (GIANT), Group of Research and Innovation in Vascular Health (GRIVAS Health), University of Bío-Bío, Chillán, Chile. Electronic address: cescudero@ubiobio.cl.
authors: Carlos
authors: C
authors: Escudero
mesh_terms: D000328:Adult; D005178:Faculty; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications* / Q000378:metabolism / Q000503:physiopathology; D050177:Overweight / Q000150:complications* / Q000378:metabolism / Q000503:physiopathology; D012463:Saliva / Q000737:chemistry*; D013061:Speech Acoustics; D014831:Voice / Q000502:physiology*; D014832:Voice Disorders / Q000175:diagnosis* / Q000209:etiology / Q000378:metabolism; D014833:Voice Quality
chemical_list: D015850:Interleukin-6
keywords: Acoustic parameter; Obesity and overweight; Salivary IL-6; Vocal loading; Voice alteration