title: Evaluation of serum antioxidants in age-related hearing loss.
abstract: BACKGROUND
  Age-related hearing loss (ARHL) has been linked to the shift in the pro-oxidant/antioxidant ratio. Our objectives were to assess serum levels of retinol and zinc among the elderly individuals and to correlate the levels with hearing threshold.
  
  
  METHODS
  Prospective study of apparently healthy individuals aged ≥60 years of age. Participants had complete clinical history, physical examination and pure tone average conducted. Blood samples were collected for determination of serum levels of retinol and zinc. Mann-Whitney U test was used to compare retinol and zinc values. Pearson's correlation test was used to determine the relationship between hearing threshold and serum levels of retinol and zinc.
  
  
  RESULTS
  Among 126 elderly participants with mean age 67 ± 2.7 years; the mean pure tone average for air conduction was 29.3 ± 1.6 dBHL while the mean bone conduction was 36.5 ± 1.8 dBHL. The median values of serum retinol and zinc levels in the elderly participants who had hearing loss in the speech frequencies were 52 and 83.3 μg/L, respectively, while among participants with normal hearing threshold, values were 50 and 89.9 μg/L, respectively (p = 0.59 and 0.99, respectively). For the high frequencies, the median value of serum retinol and zinc levels among the elderly participants with normal hearing threshold was 70.3 and 99.9 μg/L, while among those with hearing loss, it was 46.9 and 83.2 μg/L, respectively (p = 0.000 and 0.005, respectively).
  
  
  CONCLUSIONS
  Serum retinol and zinc levels were significantly lower among elderly with hearing loss involving the high frequencies. This is added evidence to extant literature on the possible role of antioxidants in the development of ARHL and suggests further study on the effect of antioxidants supplementation in the control of ARHL which is presently controversial and inconclusive.
authors.affiliation: Departments of Physiology and Oral Pathology, College of Medicine, University of Ibadan, P. O. Box 22040, Ibadan, Nigeria, jameelahlasisi@yahoo.com.
authors.forename: Taye Jemilat
authors.initials: TJ
authors.lastname: Lasisi
authors.forename: Akeem Olawale
authors.initials: AO
authors.lastname: Lasisi
mesh_terms: D000368:Aged; D000975:Antioxidants / Q000032:analysis / Q000378:metabolism; D001301:Audiometry, Pure-Tone / Q000379:methods; D001309:Auditory Threshold / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011304:Presbycusis / Q000175:diagnosis / Q000378:metabolism / Q000503:physiopathology / Q000523:psychology; D011446:Prospective Studies; D013223:Statistics as Topic; D014801:Vitamin A / Q000097:blood*; D015032:Zinc / Q000097:blood*
chemical_list: D000975:Antioxidants; D014801:Vitamin A; D015032:Zinc