title: Analysis of blood chemistry and hearing levels in a sample of older persons.
abstract: OBJECTIVE
  As part of an ongoing study of presbyacusis, the relationship between blood chemistry levels and hearing levels was investigated. Previous reports often used small sets of blood chemistry measures, and results were inconclusive. This experiment examined hearing levels and 27 measures of blood chemistry using various univariate and multivariate statistical procedures.
  
  
  METHODS
  Blood from 89 female and 128 male human subjects was collected. Subjects' ages ranged from 60 to 82 yr, and hearing levels ranged from normal to moderate/severe. Subjects with a history of middle ear disease were excluded. Electrolyte panel (Na, K, Cl, CO2, Ca, urea nitrogen, glucose, creatinine, and Mg), hematology panel (WBC, RBC, Hgb, hematocrit, platelet, etc.), serum lipids (total cholesterol, low-density lipoprotein [LDL], and high-density lipoprotein [HDL]), immunoglobulins (IgG, IgA, IgM, and IgE), and thyroxine were analyzed using univariate and multivariate statistical procedures.
  
  
  RESULTS
  Blood chemistry levels of most subjects were within normal ranges as defined by our laboratory. Correlation between blood chemistry measures and pure-tone averages (PTAs) ranged from minimal to low. Results of factor analysis, discriminant analysis, and canonical analysis showed that combining blood chemistry measures from the same panel still could not predict PTA effectively. One exception to this was a gender-specific effect of cholesterol. Hearing levels of women with high LDL/HDL ratios were 5 dB better than those of women with low LDL/HDL ratios. The comparable difference in men was only 1 dB.
  
  
  CONCLUSIONS
  Results suggest that blood chemistry measures that are primarily within the normal range have very little value in predicting pure-tone thresholds in older subjects.
authors.affiliation: Department of Otolaryngology and Communicative Sciences, Medical University of South Carolina, Charleston 29425-2242, USA.
authors.forename: F S
authors.initials: FS
authors.lastname: Lee
authors.forename: L J
authors.initials: LJ
authors.lastname: Matthews
authors.forename: J H
authors.initials: JH
authors.lastname: Mills
authors.forename: J R
authors.initials: JR
authors.lastname: Dubno
authors.forename: W Y
authors.initials: WY
authors.lastname: Adkins
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001301:Audiometry, Pure-Tone / Q000379:methods; D001309:Auditory Threshold; D001774:Blood Chemical Analysis; D001809:Blood Viscosity; D003430:Cross-Sectional Studies; D005260:Female; D006319:Hearing Loss, Sensorineural / Q000097:blood* / Q000175:diagnosis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012737:Sex Factors